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author:("Hitomi, yki")
1.  Deficiency of asparagine synthetase causes congenital microcephaly and a progressive form of encephalopathy 
Neuron  2013;80(2):10.1016/j.neuron.2013.08.013.
SUMMARY
We analyzed four families that presented with a similar condition characterized by congenital microcephaly, intellectual disability, progressive cerebral atrophy and intractable seizures. We show that recessive mutations in the ASNS gene are responsible for this syndrome. Two of the identified missense mutations dramatically reduce ASNS protein abundance, suggesting that the mutations cause loss of function. Hypomorphic Asns mutant mice have structural brain abnormalities, including enlarged ventricles and reduced cortical thickness, and show deficits in learning and memory mimicking aspects of the patient phenotype. ASNS encodes asparagine synthetase, which catalyzes the synthesis of asparagine from glutamine and aspartate. The neurological impairment resulting from ASNS deficiency may be explained by asparagine depletion in the brain, or by accumulation of aspartate/glutamate leading to enhanced excitability and neuronal damage. Our study thus indicates that asparagine synthesis is essential for the development and function of the brain but not for that of other organs.
doi:10.1016/j.neuron.2013.08.013
PMCID: PMC3820368  PMID: 24139043
2.  De novo mutations in ATP1A3 cause alternating hemiplegia of childhood 
Heinzen, Erin L. | Swoboda, Kathryn J. | Hitomi, Yuki | Gurrieri, Fiorella | Nicole, Sophie | de Vries, Boukje | Tiziano, F. Danilo | Fontaine, Bertrand | Walley, Nicole M. | Heavin, Sinéad | Panagiotakaki, Eleni | Fiori, Stefania | Abiusi, Emanuela | Di Pietro, Lorena | Sweney, Matthew T. | Newcomb, Tara M. | Viollet, Louis | Huff, Chad | Jorde, Lynn B. | Reyna, Sandra P. | Murphy, Kelley J. | Shianna, Kevin V. | Gumbs, Curtis E. | Little, Latasha | Silver, Kenneth | Ptác̆ek, Louis J. | Haan, Joost | Ferrari, Michel D. | Bye, Ann M. | Herkes, Geoffrey K. | Whitelaw, Charlotte M. | Webb, David | Lynch, Bryan J. | Uldall, Peter | King, Mary D. | Scheffer, Ingrid E. | Neri, Giovanni | Arzimanoglou, Alexis | van den Maagdenberg, Arn M.J.M. | Sisodiya, Sanjay M. | Mikati, Mohamad A. | Goldstein, David B. | Nicole, Sophie | Gurrieri, Fiorella | Neri, Giovanni | de Vries, Boukje | Koelewijn, Stephany | Kamphorst, Jessica | Geilenkirchen, Marije | Pelzer, Nadine | Laan, Laura | Haan, Joost | Ferrari, Michel | van den Maagdenberg, Arn | Zucca, Claudio | Bassi, Maria Teresa | Franchini, Filippo | Vavassori, Rosaria | Giannotta, Melania | Gobbi, Giuseppe | Granata, Tiziana | Nardocci, Nardo | De Grandis, Elisa | Veneselli, Edvige | Stagnaro, Michela | Gurrieri, Fiorella | Neri, Giovanni | Vigevano, Federico | Panagiotakaki, Eleni | Oechsler, Claudia | Arzimanoglou, Alexis | Nicole, Sophie | Giannotta, Melania | Gobbi, Giuseppe | Ninan, Miriam | Neville, Brian | Ebinger, Friedrich | Fons, Carmen | Campistol, Jaume | Kemlink, David | Nevsimalova, Sona | Laan, Laura | Peeters-Scholte, Cacha | van den Maagdenberg, Arn | Casaer, Paul | Casari, Giorgio | Sange, Guenter | Spiel, Georg | Boneschi, Filippo Martinelli | Zucca, Claudio | Bassi, Maria Teresa | Schyns, Tsveta | Crawley, Francis | Poncelin, Dominique | Vavassori, Rosaria
Nature genetics  2012;44(9):1030-1034.
Alternating hemiplegia of childhood (AHC) is a rare, severe neurodevelopmental syndrome characterized by recurrent hemiplegic episodes and distinct neurologic manifestations. AHC is usually a sporadic disorder with unknown etiology. Using exome sequencing of seven patients with AHC, and their unaffected parents, we identified de novo nonsynonymous mutations in ATP1A3 in all seven AHC patients. Subsequent sequence analysis of ATP1A3 in 98 additional patients revealed that 78% of AHC cases have a likely causal ATP1A3 mutation, including one inherited mutation in a familial case of AHC. Remarkably, six ATP1A3 mutations explain the majority of patients, including one observed in 36 patients. Unlike ATP1A3 mutations that cause rapid-onset-dystonia-parkinsonism, AHC-causing mutations revealed consistent reductions in ATPase activity without effects on protein expression. This work identifies de novo ATP1A3 mutations as the primary cause of AHC, and offers insight into disease pathophysiology by expanding the spectrum of phenotypes associated with mutations in this gene.
doi:10.1038/ng.2358
PMCID: PMC3442240  PMID: 22842232
3.  Human CD72 splicing isoform responsible for resistance to systemic lupus erythematosus regulates serum immunoglobulin level and is localized in endoplasmic reticulum 
BMC Immunology  2012;13:72.
Background
CD72 is an inhibitory co-receptor expressed on B cells. We previously demonstrated significant association of the polymorphism of the CD72 gene with susceptibility to human systemic lupus erythematosus (SLE) in individuals carrying a SLE-susceptible FCGR2B genotype (FCGR2B-232Thr/Thr). The human CD72 locus generates a splicing isoform that lacks exon 8 (CD72Δex8) as well as full-length CD72 (CD72fl), and the CD72 polymorphism regulates exon 8 skipping.
Results
Here we demonstrated that individuals carrying the disease-protective CD72 genotype exhibit significantly lower serum immunoglobulin levels than do individuals carrying other CD72 genotypes (P < 0.05). Although expression level of CD72fl in the peripheral blood B cells was similar regardless of CD72 genotype, the protein level of CD72Δex8 was increased in individuals carrying the disease-protective CD72 genotype, suggesting a crucial role of CD72Δex8 in regulation of antibody production. By expressing these human CD72 isoforms in mouse cell lines, we further demonstrated that CD72Δex8 is accumulated in endoplasmic reticulum (ER) and fails to regulate BCR signaling whereas human CD72fl is efficiently transported to the cell surface and inhibits signaling through the B cell antigen receptor (BCR), as is the case for mouse CD72.
Conclusion
Human CD72 polymorphism appears to regulate antibody production as well as susceptibility to SLE by regulating expression of ER-localizing CD72Δex8.
doi:10.1186/1471-2172-13-72
PMCID: PMC3565990  PMID: 23268649
Polymorphism; Exon skipping; C-type lectin domain
4.  Thymic Stromal Lymphopoietin Gene Promoter Polymorphisms Are Associated with Susceptibility to Bronchial Asthma 
Thymic stromal lymphopoietin (TSLP) triggers dendritic cell–mediated T helper (Th) 2 inflammatory responses. A single-nucleotide polymorphism (SNP), rs3806933, in the promoter region of the TSLP gene creates a binding site for the transcription factor activating protein (AP)–1. The variant enhances AP-1 binding to the regulatory element, and increases the promoter–reporter activity of TSLP in response to polyinosinic-polycytidylic acid (poly[I:C]) stimulation in normal human bronchial epithelium (NHBE). We investigated whether polymorphisms including the SNP rs3806933 could affect the susceptibility to and clinical phenotypes of bronchial asthma. We selected three representative (i.e., Tag) SNPs and conducted association studies of the TSLP gene, using two independent populations (639 patients with childhood atopic asthma and 838 control subjects, and 641 patients with adult asthma and 376 control subjects, respectively). We further examined the effects of corticosteroids and a long-acting β2-agonist (salmeterol) on the expression levels of the TSLP gene in response to poly(I:C) in NHBE. We found that the promoter polymorphisms rs3806933 and rs2289276 were significantly associated with disease susceptibility in both childhood atopic and adult asthma. The functional SNP rs3806933 was associated with asthma (meta-analysis, P = 0.000056; odds ratio, 1.29; 95% confidence interval, 1.14–1.47). A genotype of rs2289278 was correlated with pulmonary function. Moreover, the induction of TSLP mRNA and protein expression induced by poly(I:C) in NHBE was synergistically impaired by a corticosteroid and salmeterol. TSLP variants are significantly associated with bronchial asthma and pulmonary function. Thus, TSLP may serve as a therapeutic target molecule for combination therapy.
doi:10.1165/rcmb.2009-0418OC
PMCID: PMC3159073  PMID: 20656951
asthma; TSLP; bronchial epithelial cells; combination therapy; genetic polymorphisms
5.  Clinical application of exome sequencing in undiagnosed genetic conditions 
Journal of Medical Genetics  2012;49(6):353-361.
Background
There is considerable interest in the use of next-generation sequencing to help diagnose unidentified genetic conditions, but it is difficult to predict the success rate in a clinical setting that includes patients with a broad range of phenotypic presentations.
Methods
The authors present a pilot programme of whole-exome sequencing on 12 patients with unexplained and apparent genetic conditions, along with their unaffected parents. Unlike many previous studies, the authors did not seek patients with similar phenotypes, but rather enrolled any undiagnosed proband with an apparent genetic condition when predetermined criteria were met.
Results
This undertaking resulted in a likely genetic diagnosis in 6 of the 12 probands, including the identification of apparently causal mutations in four genes known to cause Mendelian disease (TCF4, EFTUD2, SCN2A and SMAD4) and one gene related to known Mendelian disease genes (NGLY1). Of particular interest is that at the time of this study, EFTUD2 was not yet known as a Mendelian disease gene but was nominated as a likely cause based on the observation of de novo mutations in two unrelated probands. In a seventh case with multiple disparate clinical features, the authors were able to identify homozygous mutations in EFEMP1 as a likely cause for macular degeneration (though likely not for other features).
Conclusions
This study provides evidence that next-generation sequencing can have high success rates in a clinical setting, but also highlights key challenges. It further suggests that the presentation of known Mendelian conditions may be considerably broader than currently recognised.
doi:10.1136/jmedgenet-2012-100819
PMCID: PMC3375064  PMID: 22581936
Exome sequencing; unidentified genetic conditions; medical genetics; paediatrics; clinical genetics; complex traits; genetic screening/counselling; genetics; genome-wide; psychotic disorders (including schizophrenia); molecular genetics; gastroenterology; immunology (including allergy).

Results 1-5 (5)