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1.  MYH-9 Related Platelet Disorders: Strategies for Management and Diagnosis 
MYH-9 related platelet disorders belong to the group of inherited giant platelet disorders. The MYH-9 gene encodes the non-muscular myosin heavy chain IIA (NMMHCIIA), a cytoskeletal contractile protein. Several mutations in the MYH-9 gene lead to macrothrombocytopenia, and cytoplasmic inclusion bodies within leukocytes, while the number of megakaryocytes in the bone marrow is normal. Four overlapping syndromes, known as May-Hegglin anomaly, Epstein syndrome, Fechtner syndrome and Sebastian platelet syndrome, describe different clinical manifestations of MYH9 gene mutations. Macrothrombocytopenia is present in all affected individuals, whereas only some develop additional clinical manifestations such as renal failure, hearing loss and presenile cataracts. The bleeding tendency is usually moderate, with menorrhagia and easy bruising being most frequent. The biggest risk for the individual is inappropriate treatment due to misdiagnosis of chronic autoimmune thrombocytopenia. More than 30 mutations within the 40 exons of the MYH-9 gene leading to macrothrombocytopenia have been identified, of which the upstream mutations up to amino acid ~1400 are more likely associated with syndromic manifestations than the downstream mutations. Diagnosis is based on identification of the granulocyte inclusion bodies using blood smears and immunofluorescence and is finally confirmed by identifying the mutation. Treatment is supportive and should be aimed to prevent iron deficiency anemia. Beside renal failure, the biggest risk for patients affected by a MYH-9 disorder are the adverse effects resulting form treatment based on the misdiagnosis of immune thrombocytopenia.
PMCID: PMC2980510  PMID: 21113248
MYH9 gene; Non-musclular myosin IIA; May-Hegglin anomaly; Epstein syndrome; Fechtner syndrome; Sebastian platelet syndrome; Macrothrombocytopenia
2.  Familial hypertrophic cardiomyopathy owing to double heterozygosity for a 403Arg→ Trp mutation in exon 13 of the MYH7 gene and a novel mutation, 453Arg→ His, in exon 14 of the MYH7 gene: A case report 
An unusual clinical history of a 23-year-old male proband with obstructive hypertrophic cardiomyopathy associated with a rare genotype is presented. Genetic analysis of the proband found evidence for two distinct mutations of the MYH7 gene (the gene coding for the beta-myosin heavy chain): 403Arg→ Trp in exon 13 and a novel mutation, 453Arg→ His, in exon 14. A heterozygous site mutation was identified in exon 13 in the proband’s father but no mutation site was found in his mother. Thus, the novel mutation in exon 14 is a de novo mutation.
PMCID: PMC2859004  PMID: 20428263
Beta-myosin heavy chain; Genetic mutations; Hypertrophic cardiomyopathy; MYH7 gene
3.  Cochlear implantation is safe and effective in patients with MYH9-related disease 
MYH9-related disease (MYH9-RD) is a rare syndromic disorder deriving from mutations in MYH9, the gene for the heavy chain of non-muscle myosin IIA. Patients present with congenital thrombocytopenia and giant platelets and have a variable risk of developing sensorineural deafness, kidney damage, presenile cataract, and liver abnormalities. Almost all MYH9-RD patients develop the hearing defect, which, in many individuals, progresses to severe to profound deafness with high impact on quality of life. These patients are potential candidates for cochlear implantation (CI), however, no consistent data are available about the risk to benefit ratio of CI in MYH9-RD. The only reported patient who received CI experienced perisurgery complications that have been attributed to concurrent platelet defects and/or MYH9 protein dysfunction.
By international co-operative study, we report the clinical outcome of 10 patients with MYH9-RD and severe to profound deafness who received a CI at 8 institutions.
Nine patients benefited from CI: in particular, eight of them obtained excellent performances with restoration of a practically normal hearing function and verbal communication abilities. One patient had a slightly worse performance that could be explained by the very long duration of severe deafness before CI. Finally, one patient did not significantly benefit from CI. No adverse events attributable to MYH9-RD syndrome were observed, in particular no perisurgery bleeding complications due to the platelet defects were seen. Patients’ perioperative management is described and discussed.
CI is safe and effective in most patients with MYH9-RD and severe to profound deafness and should be offered to these subjects, possibly as soon as they develop the criteria for candidacy.
PMCID: PMC4105151  PMID: 24980457
MYH9-related disease; Genetic deafness; Inherited thrombocytopenia; Cochlear implantation; Fetchner syndrome; Epstein syndrome; May-Hegglin anomaly; Non-muscle myosin
4.  Transfection of the mutant MYH9 cDNA reproduces the most typical cellular phenotype of MYH9-related disease in different cell lines 
PathoGenetics  2008;1:5.
Heterozygous mutations of MYH9, encoding the Non-Muscular Myosin Heavy Chain-IIA (NMMHC-IIA), cause a complex disorder named MYH9-related disease, characterized by a combination of different phenotypic features. At birth, patients present platelet macrocytosis, thrombocytopenia and leukocyte inclusions containing NMMHC-IIA. Moreover, later in life some of them develop the additional features of sensorineural hearing loss, cataracts and/or glomerulonephritis that sometimes leads to end stage renal failure.
To clarify the mechanism by which the mutant NMMHC-IIA could cause phenotypic anomalies at the cellular level, we examined the effect of transfection of the full-length mutated D1424H MYH9 cDNAs. We have observed, by confocal microscopy, abnormal distribution of the protein and formation of rod-like aggregates reminiscent of the leukocyte inclusions found in patients. Co-transfection of differently labeled wild-type and mutant full-length cDNAs showed the simultaneous presence of both forms of the protein in the intracellular aggregates.
These findings suggest that the NMMHC-IIA mutated in position 1424 is able to interact with the WT form in living cells, despite part of the mutant protein precipitates in non-functional aggregates. Transfection of the entire WT or mutant MYH9 in cell lines represents a powerful experimental model to investigate consequences of MYH9 mutations.
PMCID: PMC2633265  PMID: 19046415
5.  Missense mutations in the APOL1 gene are highly associated with end stage kidney disease risk previously attributed to the MYH9 gene 
Human Genetics  2010;128(3):345-350.
MYH9 has been proposed as a major genetic risk locus for a spectrum of nondiabetic end stage kidney disease (ESKD). We use recently released sequences from the 1000 Genomes Project to identify two western African-specific missense mutations (S342G and I384M) in the neighboring APOL1 gene, and demonstrate that these are more strongly associated with ESKD than previously reported MYH9 variants. The APOL1 gene product, apolipoprotein L-1, has been studied for its roles in trypanosomal lysis, autophagic cell death, lipid metabolism, as well as vascular and other biological activities. We also show that the distribution of these newly identified APOL1 risk variants in African populations is consistent with the pattern of African ancestry ESKD risk previously attributed to MYH9.
Mapping by admixture linkage disequilibrium (MALD) localized an interval on chromosome 22, in a region that includes the MYH9 gene, which was shown to contain African ancestry risk variants associated with certain forms of ESKD (Kao et al. 2008; Kopp et al. 2008). MYH9 encodes nonmuscle myosin heavy chain IIa, a major cytoskeletal nanomotor protein expressed in many cell types, including podocyte cells of the renal glomerulus. Moreover, 39 different coding region mutations in MYH9 have been identified in patients with a group of rare syndromes, collectively termed the Giant Platelet Syndromes, with clear autosomal dominant inheritance, and various clinical manifestations, sometimes also including glomerular pathology and chronic kidney disease (Kopp 2010; Sekine et al. 2010). Accordingly, MYH9 was further explored in these studies as the leading candidate gene responsible for the MALD signal. Dense mapping of MYH9 identified individual single nucleotide polymorphisms (SNPs) and sets of such SNPs grouped as haplotypes that were found to be highly associated with a large and important group of ESKD risk phenotypes, which as a consequence were designated as MYH9-associated nephropathies (Bostrom and Freedman 2010). These included HIV-associated nephropathy (HIVAN), primary nonmonogenic forms of focal segmental glomerulosclerosis, and hypertension affiliated chronic kidney disease not attributed to other etiologies (Bostrom and Freedman 2010). The MYH9 SNP and haplotype associations observed with these forms of ESKD yielded the largest odds ratios (OR) reported to date for the association of common variants with common disease risk (Winkler et al. 2010). Two specific MYH9 variants (rs5750250 of S-haplotype and rs11912763 of F-haplotype) were designated as most strongly predictive on the basis of Receiver Operating Characteristic analysis (Nelson et al. 2010). These MYH9 association studies were then also extended to earlier stage and related kidney disease phenotypes and to population groups with varying degrees of recent African ancestry admixture (Behar et al. 2010; Freedman et al. 2009a, b; Nelson et al. 2010), and led to the expectation of finding a functional African ancestry causative variant within MYH9. However, despite intensive efforts including re-sequencing of the MYH9 gene no suggested functional mutation has been identified (Nelson et al. 2010; Winkler et al. 2010). This led us to re-examine the interval surrounding MYH9 and to the detection of novel missense mutations with predicted functional effects in the neighboring APOL1 gene, which are significantly more associated with ESKD than all previously reported SNPs in MYH9.
Electronic supplementary material
The online version of this article (doi:10.1007/s00439-010-0861-0) contains supplementary material, which is available to authorized users.
PMCID: PMC2921485  PMID: 20635188
6.  Absence of MutY homologue mutation in patients with multiple sporadic adenomatous polyps in Korea 
AIM: Recently, germ-line mutation in the base excision repair gene MYH has been identified to cause a novel autosomal recessive form of familial adenomatous polyposis (FAP). Interestingly, a striking evidence for MYH mutations within different ethnic groups has been demonstrated. In this study, we screened 30 patients with multiple adenomatous polyps for MYH mutations to assess its prevalence and ethnic specificity in Korea.
METHODS: Thirty patients (21 men and 9 women; mean age 62.3 years) with multiple adenomatous polyps were examined for MYH mutations. The mean number of adenomas per patient was 10.0. Sixteen exonic regions and their intronic sequences were amplified by PCR and subjected to SSCP and DNA sequencing analyses.
RESULTS: None of the patients was identified to carry any truncating or sequence alterations in MYH. Our screening for the mutational regions, which were recognized from Caucasian patients or affected Indian families, also failed to detect sequence substitutions.
CONCLUSION: Mutation in MYH may be rarely involved in the pathogenesis of multiple sporadic colorectal adenomas in Korean population, although a large-scale analysis will be required to clarify the presence of specific MYH variants in a subset of patients and their role in the predisposition of multiple colorectal adenomas in Korean population.
PMCID: PMC4066163  PMID: 16521226
MY; Multiple adenomatous polyps; Germ-line mutation; Familial adenomatous polyposis; Ethnic difference
7.  A novel mutation expands the genetic and clinical spectrum of MYH7-related myopathies 
Neuromuscular disorders : NMD  2013;23(5):432-436.
MYH7 mutations are an established cause of Laing distal myopathy, myosin storage myopathy, and cardiomyopathy, as well as additional myopathy subtypes. We report a novel MYH7 mutation (p.Leu1597Arg) that arose de novo in two unrelated probands. Proband 1 has a myopathy characterized by distal weakness and prominent contractures and histopathology typical of multi-minicore disease. Proband 2 has an axial myopathy and histopathology consistent with congenital fiber type disproportion. These cases highlight the broad spectrum of clinical and histological patterns associated with MYH7 mutations, and provide further evidence that MYH7 is likely responsible for a greater proportion of congenital myopathies than currently appreciated.
PMCID: PMC4103162  PMID: 23478172
Congenital myopathies; MYH7; Laing distal myopathy; Axial myopathy
8.  Mutation spectrum and genotype-phenotype correlations in a large French cohort of MYH9-Related Disorders 
MYH9-Related Disorders are a group of rare autosomal dominant platelet disorders presenting as nonsyndromic forms characterized by macrothrombocytopenia with giant platelets and leukocyte inclusion bodies or as syndromic forms combining these hematological features with deafness and/or nephropathy and/or cataracts. They are caused by mutations in the MYH9 gene encoding the nonmuscle myosin heavy chain II-A (NMMHC-IIA). Until now, at least 49 MYH9 mutations have been reported in isolated cases or small series but only rarely in large series. We report the results of an 8-year study of a large cohort of 109 patients from 37 sporadic cases and 39 unrelated families. We have identified 43 genetic variants, 21 of which are novel to our patients. A majority, 33 (76.7%), were missense mutations and six exons were preferentially targeted, as previously published. The other alterations were three deletions of one nucleotide, one larger deletion of 21 nucleotides, and one duplication. For the first time, a substitution T>A was found in the donor splice site of intron 40 (c.5765+2T>A). Seven patients, four from the same family, had two genetic variants. The analysis of the genotype-phenotype relationships enabled us to improve the knowledge of this heterogeneous but important rare disease.
PMCID: PMC4113270  PMID: 25077172
Inherited platelet disorders; leukocyte inclusions; macrothrombocytopenia; mutation analysis; MYH9-RD
9.  A Novel Arginine to Tryptophan (R144W) Mutation in Troponin T (cTnT) Gene in an Indian Multigenerational Family with Dilated Cardiomyopathy (FDCM) 
PLoS ONE  2014;9(7):e101451.
Cardiomyopathy is a major cause of heart failure and sudden cardiac death; several mutations in sarcomeric protein genes have been associated with this disease. Our aim in the present study is to investigate the genetic variations in Troponin T (cTnT) gene and its association with dilated cardiomyopathy (DCM) in south-Indian patients. Analyses of all the exons and exon-intron boundaries of cTnT in 147 DCM and in 207 healthy controls had revealed a total of 15 SNPs and a 5 bp INDEL; of which, polymorphic SNPs were compared with the HapMap population data. Interestingly, a novel R144W mutation, that substitutes polar-neutral tryptophan for a highly conserved basic arginine in cTnT, altering the charge drastically, was identified in a DCM, with a family history of sudden-cardiac death (SCD). This mutation was found within the tropomyosin (TPM1) binding domain, and was evolutionarily conserved across species, therefore it is expected to have a significant impact on the structure and function of the protein. Family studies had revealed that the R144W is co-segregating with disease in the family as an autosomal dominant trait, but it was completely absent in 207 healthy controls and in 162 previously studied HCM patients. Further screening of the proband and three of his family members (positive for R144W mutant) with eight other genes β-MYH7, MYBPC3, TPM1, TNNI3, TTN, ACTC, MYL2 and MYL3, did not reveal any disease causing mutation, proposing the absence of compound heterozygosity. Therefore, we strongly suggest that the novel R144W unique/private mutant identified in this study is associated with FDCM. This is furthermore signifying the unique genetic architecture of Indian population.
PMCID: PMC4081629  PMID: 24992688
10.  Transient neonatal diabetes mellitus caused by a de novo ABCC8 gene mutation 
Korean Journal of Pediatrics  2011;54(4):179-182.
Transient neonatal diabetes mellitus (TNDM) is a rare form of diabetes mellitus that presents within the first 6 months of life with remission in infancy or early childhood. TNDM is mainly caused by anomalies in the imprinted region on chromosome 6q24; however, recently, mutations in the ABCC8 gene, which encodes sulfonylurea receptor 1 (SUR1), have also been implicated in TNDM. Herein, we present the case of a male child with TNDM whose mutational analysis revealed a heterozygous c.3547C>T substitution in the ABCC8 gene, leading to an Arg1183Trp mutation in the SUR1 protein. The parents were clinically unaffected and did not show a mutation in the ABCC8 gene. This is the first case of a de novo ABCC8 gene mutation in a Korean patient with TNDM. The patient was initially treated with insulin and successfully switched to sulfonylurea therapy at 14 months of age. Remission of diabetes had occurred at the age of 16 months. Currently, the patient is 21 months old and is euglycemic without any insulin or oral hypoglycemic agents. His growth and physical development are normal, and there are no delays in achieving neurological and developmental milestones.
PMCID: PMC3127153  PMID: 21738553
Diabetes mellitus; Infant; Sulfonylurea receptor; Mutation
11.  A new variant of Glanzmann's thrombasthenia (Strasbourg I). Platelets with functionally defective glycoprotein IIb-IIIa complexes and a glycoprotein IIIa 214Arg----214Trp mutation. 
Journal of Clinical Investigation  1992;89(6):1995-2004.
We describe a new variant of Glanzmann's thrombasthenia (variant Strasbourg I). The patient (M.S.) showed an absence of platelet aggregation to ADP, thrombin, and collagen, and a decreased clot retraction. Platelet fibrinogen was approximately 20% of normal levels. ADP-stimulated platelets bound markedly reduced amounts of soluble fibrinogen and platelet adhesion to surface-bound fibrinogen was defective. Normal to subnormal amounts of glycoprotein (GP) IIb-IIIa (alpha IIb beta 3) complexes, the platelet fibrinogen receptor, were revealed by SDS-PAGE, crossed immunoelectrophoresis, and antibody binding. However, the complexes were unusually sensitive to dissociation with EDTA at room temperature. Furthermore, flow cytometry showed that the platelets failed to bind the activation-dependent monoclonal antibody, PAC-1, after stimulation. In contrast, an RGDS-containing peptide induced significant binding of the anti-ligand-induced binding site antibody, D3GP3, suggesting the presence of a functional RGD binding domain on the patient's GPIIb-IIIa complex. Sequence analysis was performed after polymerase chain reaction amplification of selected patient's GPIIIa exons, and of the patient's platelet GPIIb and GPIIIa mRNAs. A point mutation (C to T) was localized in exon D (iv) of GPIIIa that resulted in an 214Arg to 214Trp amino acid substitution. The defect has been inherited from the parents who are heterozygous for the same mutation. This substitution points to an essential amino acid in a region of GPIIIa involved in the binding of fibrinogen and influencing the Ca(2+)-dependent stability of the GPIIb-IIIa complex.
PMCID: PMC295902  PMID: 1602006
12.  Missense mutation in PFKM associated with muscle-type phosphofructokinase deficiency in the Wachtelhund dog 
Molecular and cellular probes  2012;26(6):243-247.
Hereditary muscle-type phosphofructokinase (PFK) deficiency causing intermittent hemolytic anemia and exertional myopathy due to a single nonsense mutation in PFKM has been previously described in English Springer and American Cocker Spaniels, Whippets, and mixed breed dogs. We report here on a new missense mutation associated with PFK deficiency in Wachtelhunds.
Coding regions of the PFKM gene were amplified from genomic DNA and/or cDNA reverse-transcribed from RNA of EDTA blood of PFK-deficient and clinically healthy Wachtelhunds and control dogs. The amplicons were sequenced and compared to the published canine PFKM sequence. A point mutation (c.550C>T, in the coding sequence of PFKM expressed in blood) was found in all 4 affected Wachtelhunds. This missense mutation results in an amino acid substitution of arginine (Arg) to tryptophan (Trp) at position 184 of the protein expressed in blood (p.Arg184Trp). The mutation is located within an alpha-helix, and based on the SIFT analysis, this amino acid substitution is not tolerated. Amplifying the region around this mutation and digesting the PCR fragment with the restriction enzyme MspI, produces fragments that readily differentiate between PFK-deficient, carrier, and normal animals. Furthermore, we document 2 additional upstream PFKM exons expressed in canine testis but not in blood.
Despite their similar phenotypic appearance and use for hunting, Wachtelhunds and English Springer Spaniels are not thought to have common ancestors. Thus, it is not surprising that different mutations are responsible for PFK deficiency in these breeds. Knowledge of the molecular basis of PFK deficiency in Wachtelhunds provides an opportunity to screen and control the spread of this deleterious trait.
PMCID: PMC3485442  PMID: 22446493
Hemolytic anemia; Red cell defect; Myopathy; Hereditary disease; Dog
13.  The fraction of strongly bound cross-bridges is increased in mice that carry the myopathy-linked myosin heavy chain mutation MYH4L342Q 
Disease Models & Mechanisms  2013;6(3):834-840.
Myosinopathies have emerged as a new group of diseases and are caused by mutations in genes encoding myosin heavy chain (MyHC) isoforms. One major hallmark of these diseases is skeletal muscle weakness or paralysis, but the underlying molecular mechanisms remain unclear. Here, we have undertaken a detailed functional study of muscle fibers from Myh4arl mice, which carry a mutation that provokes an L342Q change within the catalytic domain of the type IIb skeletal muscle myosin protein MYH4. Because homozygous animals develop rapid muscle-structure disruption and lower-limb paralysis, they must be killed by postnatal day 13, so all experiments were performed using skeletal muscles from adult heterozygous animals (Myh4arl/+). Myh4arl/+ mice contain MYH4L342Q expressed at 7% of the levels of the wild-type (WT) protein, and are overtly and histologically normal. However, mechanical and X-ray diffraction pattern analyses of single membrane-permeabilized fibers revealed, upon maximal Ca2+ activation, higher stiffness as well as altered meridional and equatorial reflections in Myh4arl/+ mice when compared with age-matched WT animals. Under rigor conditions, by contrast, no difference was observed between Myh4arl/+ and WT mice. Altogether, these findings prove that, in adult MYH4L342Q heterozygous mice, the transition from weak to strong myosin cross-bridge binding is facilitated, increasing the number of strongly attached myosin heads, thus enhancing force production. These changes are predictably exacerbated in the type IIb fibers of homozygous mice, in which the embryonic myosin isoform is fully replaced by MYH4L342Q, leading to a hypercontraction, muscle-structure disruption and lower-limb paralysis. Overall, these findings provide important insights into the molecular pathogenesis of skeletal myosinopathies.
PMCID: PMC3634666  PMID: 23335206
14.  First description of germline mosaicism in familial hypertrophic cardiomyopathy 
Journal of Medical Genetics  2000;37(2):132-134.
Familial hypertrophic cardiomyopathy is a genetically and phenotypically heterogeneous disease caused by mutations in seven sarcomeric protein genes. It is known to be transmitted as an autosomal dominant trait with rare de novo mutations.
A French family in which two members are affected by hypertrophic cardiomyopathy was clinically screened with electrocardiography and echocardiography. Genetic analyses were performed on leucocyte DNA by haplotype analysis with microsatellite markers at the MYH7 locus and mutation screening by single strand conformation polymorphism analysis. Two subjects exhibited severe hypertrophic cardiomyopathy. A mutation in the MYH7 gene was found in exon 14 (Arg453Cys). The two affected patients were carriers of the mutation, which was not found in the circulating lymphocytes of their parents. Haplotype analysis at the MYH7 locus with two intragenic microsatellite markers (MYOI and MYOII) and the absence of the mutation in the father's sperm DNA suggested that the mutation had been inherited from the mother. However, it was not found in either her fibroblasts or hair.
This is the first description of germline mosaicism shown by molecular genetic analysis in an autosomal dominant disorder and more especially in hypertrophic cardiomyopathy. This mosaicism had been inherited from the mother but did not affect her somatic cells. Such a phenomenon might account for some de novo mutations in familial hypertrophic cardiomyopathy.

Keywords: hypertrophic cardiomyopathy; germline mosaicism; β myosin heavy chain; genetics
PMCID: PMC1734529  PMID: 10662815
15.  Coagulopathy in patients with hemorrhagic fever with renal syndrome. 
Hemorrhagic fever with renal syndrome in Korea (Korean hemorrhagic fever) is an acute viral disease characterized by fever, hemorrhage and renal failure. In Korean patients, the disease manifests more distinctive bleeding tendencies than those of hemorrhagic fever with renal syndrome found in western countries. To investigate the nature and role of the coagulation, fibrinolysis, kinin and immune system in the pathogenesis of such a hemorrhagic manifestation, alterations of these systems were assessed from the early phase of the disease. Decreased platelet count and shortened platelet survival were observed with giant platelets in the peripheral blood. The marked prolongations of bleeding time, prothrombin time and partial thromboplastin time were noticed with the decreased plasma activities of coagulation factors II, V, VIII, IX and X. Shortened half life of fibrinogen, increased fibrinogen-fibrin degradation product, with decreased plasma levels and activities of plasminogen, alpha 2-plasmin inhibitor and antithrombin III were found. On thrombelastogram, the existence of procoagulant activity was confirmed, and prolonged reaction time and clot formation time with decreased maximum amplitude were observed. The appearance of circulating immune complexes was found along with decreased C3 and normal C4 in the serum. Significant decrease of serum C3 was evident in the patients with disseminated intravascular coagulation. These findings of coagulopathy were normalized within ten days of the illness in most cases. Therefore, it can be concluded that disseminated intravascular coagulation and thrombocytopenia in the early phase, and azotemia developing later might play an important role in the pathogenesis of bleeding tendency in Korean hemorrhagic fever.
PMCID: PMC3053648  PMID: 3151765
16.  Myozenin 2 Is a Novel Gene for Human Hypertrophic Cardiomyopathy 
Circulation research  2007;100(6):766-768.
Hypertrophic cardiomyopathy (HCM) is a genetic disorder caused by mutations in sarcomeric proteins (excluding phenocopy). The causal genes in approximately one-third of the cases remain unknown. We identified a family comprised of 6 clinically affected members. The phenotype was characterized by early onset of symptoms, pronounced cardiac hypertrophy, and cardiac arrhythmias. We excluded MYH7, MYBPC3, TNNT2, and ACTC1 as the causal gene either by direct sequencing or by haplotype analysis. To map the putative candidate sarcomeric gene, we perforbold locus-specific haplotyping to detect cosegregation of the locus haplotype with the phenotype, followed by mutation screening. We genotyped 5 short-tandem-repeat markers that spanned a 4.4-centimorgan region on 4q26-q27 locus and encompassed myozenin 2 (MYOZ2), a Z-disk protein. The maximum logarithm of odds score was 2.03 (P=0.005). All affected members shared a common haplotype, implicating MYOZ2 as the causal gene. To detect the causal mutation, we sequenced all exons and exon–intron boundaries of MYOZ2 in 10 family members and identified a T→C missense mutation corresponding to S48P substitution, which cosegregated with inheritance of HCM (N=6). It was absent in 4 clinically normal family members and in 658 additional normal individuals. To determine frequency of the MYOZ2 mutations in HCM, we sequenced MYOZ2 in 516 HCM probands and detected another missense mutation (I246M). It was absent in 2 normal family members and 517 controls. Both mutations affect highly conserved amino acids. We conclude MYOZ2 is a novel causal gene for human HCM.
PMCID: PMC2775141  PMID: 17347475
mutation; gene; hypertrophic cardiomyopathy; calsarcin 1
17.  MYH9-related disease: Five novel mutations expanding the spectrum of causative mutations and confirming genotype/phenotype correlations 
MYH9-related disease (MYH9-RD) is a rare autosomal dominant syndromic disorder caused by mutations in MYH9, the gene encoding for the heavy chain of non-muscle myosin IIA (myosin-9). MYH9-RD is characterized by congenital macrothrombocytopenia and typical inclusion bodies in neutrophils associated with a variable risk of developing sensorineural deafness, presenile cataract, and/or progressive nephropathy. The spectrum of mutations responsible for MYH9-RD is limited. We report five families, each with a novel MYH9 mutation. Two mutations, p.Val34Gly and p.Arg702Ser, affect the motor domain of myosin-9, whereas the other three, p.Met847_Glu853dup, p.Lys1048_Glu1054del, and p.Asp1447Tyr, hit the coiled-coil tail domain of the protein. The motor domain mutations were associated with more severe clinical phenotypes than those in the tail domain.
PMCID: PMC3546164  PMID: 23123319
MYH9-related disease; MYH9 gene; Mutational screening; Missense mutation; In frame deletion/duplication; Genotype–phenotype correlation
18.  Haematological effects of chronic benzene poisoning in 217 workers 
Aksoy, M., Dinçol, K., Akgün, T., Erdem, Ş and Dinçol, G. (1971).Brit. J. industr. Med.,28, 296-302. Haematological effects of chronic benzene poisoning in 217 workers. A haematological study consisting of the determination of RBC, WBC, PCV, platelets, and differential counts was carried out, together with bone marrow puncture and haemoglobin analyses in appropriate cases, on a control population of 100 normal people and on 217 male labourers, 95% of whom worked with solvents containing benzene in small shops manufacturing shoes under unhygienic conditions. The concentration of benzene in the workplaces ranged between 30 and 210 p.p.m., and the period of exposure between 3 months and 17 years.
In 51 of the 217 workers (23·50%) haematological abnormalities attributable to chronic benzene poisoning were detected. Thus, leucopenia was present in 9·70%, thrombocytopenia in 1·84%, leucopenia associated with thrombocytopenia in 4·6%, pancytopenia in 2·76%, acquired pseudo-Pelger-Huet anomaly in 0·46%, lymphocytosis in 0·46%, giant platelets in 0·46%, eosinophilia in 2·30%, basophilia in 0·46%, and eosinophilia associated with basophilia in 0·46% (the maximum normal levels for eosinophils and basophils were 8% and 2% respectively).
Acquired pseudo-Pelger-Huet anomaly was detected in a worker with heterozygous betathalassaemia (HbA2 4·1% and HbF 8·7%) in whom the only effect of benzene was on the leucocyte nuclei, all other haematological values being within normal limits. On the other hand, in 33·1% of the workers the haemoglobin was less than 12 g/100 ml and in 32·7% the PCV was less than 40% with the MCV ranging between 86 and 96 μm3. In none of them did MCV exceed 100 μm3. Thirty-one per cent. of these anaemic workers were treated with adequate doses of oral iron, which resulted, in all cases, in a complete disappearance of the anaemia. Therefore, it is difficult to attribute this anaemia to the effect of benzene alone.
Thus it is concluded that benzene exerts its harmful effect, primarily on the leucocytes, with eosinophilia and basophilia as inconstant findings, secondarily on the platelets causing thrombocytopenia, and finally on all three series giving rise to pancytopenia.
PMCID: PMC1069505  PMID: 5557851
19.  A novel mutation of the Keratin 12 gene responsible for a severe phenotype of Meesmann's corneal dystrophy 
Molecular Vision  2007;13:975-980.
To determine if a mutation within the coding region of the keratin 12 gene (KRT12) is responsible for a severe form of Meesmann's corneal dystrophy.
A family with clinically identified Meesmann's corneal dystrophy was recruited and studied. Electron microscopy was performed on scrapings of corneal epithelial cells from the proband. Mutations in the KRT12 gene were sought using direct genomic sequencing of leukocyte DNA from two affected and two unaffected family members. Subsequently, the observed mutation was screened in all available family members using polymerase chain reaction and direct sequencing.
A heterozygous missense mutation (Arg430Pro) was found in exon 6 of KRT12 in all 14 affected individuals studied. Unaffected family members and 100 normal controls were negative for this mutation.
We have identified a novel mutation in the KRT12 gene that is associated with a symptomatic phenotype of Meesmann's corneal dystrophy. This mutation results in a substitution of proline for arginine in the helix termination motif that may disrupt the normal helix, leading to a dramatic structural change of the keratin 12 protein.
PMCID: PMC2774455  PMID: 17653038
20.  Germline MutY Human Homologue Mutations and Colorectal Cancer: A Multisite Case-Control Study 
Gastroenterology  2008;136(4):1251-1260.
Background & Aims
The MutY human homologue (MYH) gene is a member of the base-excision repair pathway involved in the repair of oxidative DNA damage. The objective of this study was to determine colorectal cancer (CRC) risk associated with mutations in the MYH gene.
A total of 3811 CRC cases and 2802 controls collected from a multisite CRC registry were screened for 9 germline MYH mutations; subjects with any mutation underwent screening of the entire MYH gene. Logistic regression was used to estimate age- and sex-adjusted odds ratios (AOR). Clinicopathologic and epidemiologic data were reviewed to describe the phenotype associated with MYH mutation status and assess for potential confounding and effect modification.
Twenty-seven cases and 1 control subject carried homozygous or compound heterozygous MYH mutations (AOR, 18.1; 95% confidence interval, 2.5–132.7). CRC cases with homozygous/compound heterozygous mutations were younger at diagnosis (P = .01), had a higher proportion of right-sided (P = .01), synchronous cancers (P < .01), and personal history of adenomatous polyps (P = .003). Heterozygous MYH mutations were identified in 87 CRC cases and 43 controls; carriers were at increased risk of CRC (AOR, 1.48; 95% confidence interval, 1.02–2.16). There was a higher prevalence of low-frequency microsatellite instability (MSI) in tumors from heterozygous and homozygous/compound heterozygous MYH mutation carriers (P = .02); MSI status modified the CRC risk associated with heterozygous MYH mutations (P interaction < .001).
Homozygous/compound heterozygous MYH mutations account for less than 1% of CRC cases. Heterozygous carriers are at increased risk of CRC. Further studies are needed to understand the possible interaction between the base excision repair and low-frequency MSI pathways.
PMCID: PMC2739726  PMID: 19245865
21.  Molecular and functional analysis of a novel MEK2 mutation in cardio-facio-cutaneous syndrome: Transmission through four generations 
Cardio-facio-cutaneous (CFC) syndrome is one of the RASopathies and is caused by alteration of activity through the Ras/mitogen-activated protein kinase (MAPK) pathway due to heterozygous de novo mutations in protein kinases BRAF, MEK1 or MEK2. CFC is a rare multiple congenital anomaly disorder in which individuals have characteristic dysmorphic features, cardiac defects, ectodermal anomalies and developmental delay. We report a 7 ½ month-old boy with a clinical diagnosis of CFC. Bidirectional sequence analysis of MEK2 revealed a novel c.383C→A transition in exon 3 resulting in a nonsynonymous missense substitution, p.P128Q. Other family members, including the proband’s mother and half-sibling, displayed phenotypic features of CFC and were also screened for the MEK2 mutation identified in the proband. SIFT (Sorting Intolerant From Tolerant) analysis determined the novel MEK2 p.P128Q to be deleterious. To corroborate the functional alteration of the novel mutant protein, transient transfection of 293T cells with subsequent Western analysis was used to demonstrate increased kinase activity, as measured by ERK phosphorylation. This first reported case of a vertically transmitted functional CFC MEK mutation further expands our understanding of germline mutations within the Ras/MAPK pathway.
PMCID: PMC4180666  PMID: 20358587
acute lymphoblastic leukemia; autosomal dominant; cardio-facio-cutaneous syndrome; BRAF; MEK1; MEK2; RASopathy; Ras/MAPK; signal transduction pathway; multiple generation transmission
22.  Molecular basis of von Willebrand disease type IIB. Candidate mutations cluster in one disulfide loop between proposed platelet glycoprotein Ib binding sequences. 
Journal of Clinical Investigation  1991;87(4):1220-1226.
Many variants of von Willebrand disease (vWD) with qualitatively abnormal von Willebrand factor (vWF) are recognized. In vWD type IIB, the abnormal protein displays enhanced affinity for a platelet vWF receptor, the glycoprotein Ib-IX complex. 14 patients from 7 unrelated families with vWD type IIB were studied to determine the molecular basis for this phenotype. Specific oligonucleotide primers were used to amplify portions of vWF exon 28 encoding a domain that interacts with the platelet glycoprotein Ib-IX complex. Candidate missense mutations were identified for all 14 patients by DNA sequencing, allele specific oligonucleotide hybridization, and restriction endonuclease digestion. These sequence changes occur in an 11 amino acid segment within a single disulfide loop bounded by Cys(509) and Cys(695). All of these sequence changes are C----T transitions within CG dinucleotides. Six patients from two unrelated families were heterozygous for the encoded sequence Arg(543)----Trp. Seven patients from four unrelated families were heterozygous for the encoded sequence Arg(545)----Cys; this sequence change appears to have occurred independently three times, once as a new spontaneous mutation. One patient with apparently sporadic vWD type IIB was heterozygous for the encoded sequence Val(553)----Met, and this appears to be a new mutation. None of these sequence changes was found in 100 normal alleles. These findings suggest that vWD type IIB may be caused by relatively few distinct mutations, that these mutations may cluster within a specific region of one disulfide loop in vWF domain A1, and that this region can modulate the affinity of vWF for the platelet glycoprotein Ib-IX complex.
PMCID: PMC295140  PMID: 2010538
23.  Hypertrophic cardiomyopathy: from mutation to functional analysis of defective protein 
Croatian Medical Journal  2011;52(3):384-391.
To analyze the genesis of hypertrophic cardiomyopathy on a large cohort of patients from molecular genetics point of view and perform the functional analysis of the 3D molecular model of defective myosin-7 protein in silico.
The study enrolled 153 patients with diagnosed hypertrophic cardiomyopathy from different parts of the Czech Republic. DNA samples were analyzed for mutations in exons 21 and 22 of the MYH7 gene, which have been associated with high mutation clustering. The 3D model of human myosin-7 was built using the x-ray structure of nucleotide-free scallop myosin S1 as the structural template. We performed de novo structure prediction of mutant and wild type peptides spanning the 769-788 amino acids region of the myosin-7 protein.
The Arg870His and Asp778Val amino acid alterations were found in 2 unrelated patients with a severe form of hypertrophic cardiomyopathy. The Asp778Val variation was chosen for subsequent 3D molecular modeling in silico. The mutation of the Asp by Val not only changes the character of the interaction pattern with other amino acids or ions but Val, being a small hydrophobic amino acid, can also completely change the stability of the region.
Mutation location in the MYH7 gene and changes in amino acid composition may have a crucial negative impact on the outcome of the disease in patients with hypertrophic cardiomyopathy. In addition, a mutation that changes the charge of the amino acid is more likely to affect protein function than a conservative mutation.
PMCID: PMC3118724  PMID: 21674835
24.  Identification of platelet function defects by multi-parameter assessment of thrombus formation 
Nature Communications  2014;5:4257.
Assays measuring platelet aggregation (thrombus formation) at arterial shear rate mostly use collagen as only platelet-adhesive surface. Here we report a multi-surface and multi-parameter flow assay to characterize thrombus formation in whole blood from healthy subjects and patients with platelet function deficiencies. A systematic comparison is made of 52 adhesive surfaces with components activating the main platelet-adhesive receptors, and of eight output parameters reflecting distinct stages of thrombus formation. Three types of thrombus formation can be identified with a predicted hierarchy of the following receptors: glycoprotein (GP)VI, C-type lectin-like receptor-2 (CLEC-2)>GPIb>α6β1, αIIbβ3>α2β1>CD36, α5β1, αvβ3. Application with patient blood reveals distinct abnormalities in thrombus formation in patients with severe combined immune deficiency, Glanzmann’s thrombasthenia, Hermansky–Pudlak syndrome, May–Hegglin anomaly or grey platelet syndrome. We suggest this test may be useful for the diagnosis of patients with suspected bleeding disorders or a pro-thrombotic tendency.
Platelets from patients with bleeding disorders often display altered adherence to surface proteins. In this study, de Witt et al. design a flow chamber for the systematic interrogation of platelets attaching to 52 adhesive surfaces, which may be helpful for the diagnosis of platelet disorders.
PMCID: PMC4109023  PMID: 25027852
25.  TGFBI and CHST6 gene analysis in Chinese stromal corneal dystrophies 
To investigate whether mutations in TGFBI gene or CHST6 gene correlated with stromal corneal dystrophies (CD) in 8 Chinese probands.
Eight unrelated patients with stromal corneal dystrophies were recruited in this study; all affected members were assessed by completely ophthalmologic examinations. Genomic DNA was extracted from peripheral leukocytes, 17 exons of TGFBI gene and the exon of CHST6 gene were amplified by polymerase chain reaction (PCR), sequenced directly and compared with the reference database.
Three heterozygous mutations in TGFBI gene were identified in six patients: c. 370C>T (p.Arg124Cys) was found in exon 4 of TGFBI gene in three members, c. 371G>A (p.Arg124His) was found in one patient; c. 1663C>T (p.Arg555Trp) was found in exon 12 in other two members. In addition, four polymorphisms with the nucleotide changes rs1442, rs1054124, rs4669, and rs35151677 were found in TGFBI gene. Mutations were not identified in the rest of 2 affected individuals in TGFBI gene or CHST6 gene.
Within these patients, R124C, R124H and R555W mutations were co-segregated with the disease phenotypes and were specific mutations for lattice corneal dystrophy type I (LCD I), Avellino corneal dystrophy (ACD, GCD II), granular corneal dystrophy type I (GCD I), respectively. Our study highlights the prevalence of codon 124 and codon 555 mutations in the TGFBI gene among the Chinese stromal corneal dystrophies patients.
PMCID: PMC3388397  PMID: 22773977
corneal dystrophies; Mutation screening; TGFBI gene; TGFBI protein; carbohydrate; sulfotransferse CHST6

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