Search tips
Search criteria

Results 1-15 (15)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
author:("Xiao, jinfeng")
1.  Role of Gα(olf) in familial and sporadic adult-onset primary dystonia 
Human Molecular Genetics  2013;22(12):2510-2519.
The vast majority of patients with primary dystonia are adults with focal or segmental distribution of involuntary movements. Although ∼10% of probands have at least one first- or second-degree relative to dystonia, large families suited for linkage analysis are exceptional. After excluding mutations in known primary dystonia genes (TOR1A, THAP1 and CIZ1), whole-exome sequencing identified a GNAL missense mutation (c.682G>T, p.V228F) in an African-American pedigree with clinical phenotypes that include cervical, laryngeal and hand-forearm dystonia. Screening of 760 subjects with familial and sporadic primary dystonia identified three Caucasian pedigrees with GNAL mutations [c.591dupA (p.R198Tfs*13); c.733C>T (p.R245*); and c.3G>A (p.M1?)]. These mutations show incomplete penetrance. Our findings corroborate those of a recent study which used whole-exome sequencing to identify missense and nonsense GNAL mutations in Caucasian pedigrees of mixed European ancestry with mainly adult-onset cervical and segmental dystonia. GNAL encodes guanine nucleotide-binding protein G(olf), subunit alpha [Gα(olf)]. Gα(olf) plays a role in olfaction, coupling D1 and A2a receptors to adenylyl cyclase, and histone H3 phosphorylation. African-American subjects harboring the p.V228F mutation exhibited microsmia. Lymphoblastoid cell lines from subjects with the p.V228F mutation showed upregulation of genes involved in cell cycle control and development. Consistent with known sites of network pathology in dystonia, immunohistochemical studies indicated that Gα(olf) is highly expressed in the striatum and cerebellar Purkinje cells, and co-localized with corticotropin-releasing hormone receptors in the latter.
PMCID: PMC3658169  PMID: 23449625
2.  A rare sequence variant in intron 1 of THAP1 is associated with primary dystonia 
Although coding variants in THAP1 have been causally associated with primary dystonia, the contribution of noncoding variants remains uncertain. Herein, we examine a previously identified Intron 1 variant (c.71+9C>A, rs200209986). Among 1672 subjects with mainly adult-onset primary dystonia, 12 harbored the variant in contrast to 1/1574 controls (P < 0.01). Dystonia classification included cervical dystonia (N = 3), laryngeal dystonia (adductor subtype, N = 3), jaw-opening oromandibular dystonia (N = 1), blepharospasm (N = 2), and unclassified (N = 3). Age of dystonia onset ranged from 25 to 69 years (mean = 54 years). In comparison to controls with no identified THAP1 sequence variants, the c.71+9C>A variant was associated with an elevated ratio of Isoform 1 (NM_018105) to Isoform 2 (NM_199003) in leukocytes. In silico and minigene analyses indicated that c.71+9C>A alters THAP1 splicing. Lymphoblastoid cells harboring the c.71+9C>A variant showed extensive apoptosis with relatively fewer cells in the G2 phase of the cell cycle. Differentially expressed genes from lymphoblastoid cells revealed that the c.71+9C>A variant exerts effects on DNA synthesis, cell growth and proliferation, cell survival, and cytotoxicity. In aggregate, these data indicate that THAP1 c.71+9C>A is a risk factor for adult-onset primary dystonia.
PMCID: PMC4049367  PMID: 24936516
Dystonia; DYT6; intronic variant; minigene assay; THAP1
3.  Neural expression of the transcription factor THAP1 during development in rat 
Neuroscience  2012;231:282-295.
Loss of function mutations in THAP1 have been associated with primary generalized and focal dystonia in children and adults. THAP1 encodes a transcription factor (THAP1) that harbors an atypical zinc finger domain and plays a critical role in G1-S cell cycle control. Current thinking suggests that dystonia may be a neurodevelopmental circuit disorder. Hence, THAP1 may participate in the development of the nervous system. Herein, we report the neurodevelopmental expression patterns of Thap1 transcript and THAP1 protein from the early postnatal period through adulthood in rat brain, spinal cord and dorsal root ganglia (DRG). We detected Thap1 transcript and THAP1-immunoreactivity (IR) in cerebral cortex, cerebellum, striatum, substantia nigra, thalamus, spinal cord and DRG. Thap1 transcript expression was higher in brain than in spinal cord and DRG at P1 and P7 and declined to similar levels at P14 and later time points in all regions except cerebellum, where it remained high through adulthood. In brain, THAP1 expression was highest in early development, particularly in cerebellum at P7. In addition to Purkinje cells in the cerebellum, THAP1-IR was also localized to pyramidal neurons in cerebral cortex, relay neurons in thalamus, medium spiny and cholinergic neurons in striatum, dopaminergic neurons in substantia nigra, and pyramidal and interneurons in hippocampus. In cerebellar cortex, THAP1-IR was prominently distributed in the perikarya and proximal dendrites of Purkinje cells at early time-points. In contrast, it was more diffusely distributed throughout the dendritic arbor of adult Purkinje cells producing a moderate diffuse staining pattern in the molecular layer. At all time points, nuclear IR was weaker than cytoplasmic IR. The prominent cytoplasmic and developmentally-regulated expression of THAP1 suggests that THAP1 may function as part of a cell surface-nucleus signaling cascade involved in terminal neural differentiation.
PMCID: PMC3558550  PMID: 23219941
THAP1; Purkinje cells; cerebellum; dystonia; DYT6; transcription factor
4.  Zygotic G2/M Cell Cycle Arrest Induced by ATM/Chk1 Activation and DNA Repair in Mouse Embryos Fertilized with Hydrogen Peroxide-Treated Epididymal Mouse Sperm 
PLoS ONE  2013;8(9):e73987.
Human sperm cryopreservation for assisted reproduction is compromised by ROS-induced sperm cryodamage. Our previous model study in which mouse sperm were treated with H2O2 to simulate sperm DNA-damage caused by cryopreservation-induced ROS have discovered that mouse embryos fertilized with treated sperm showed a delay in cleavage that might be associated with cell cycle arrest. The DNA-damage checkpoint pathway underlying the delay remained elusive. Moreover, our previous study have also indicated that γH2AX, the DNA-damage repair marker, was functional in mouse embryos similarly fertilized, but the completeness and correctness are unknown and warrant more studies because insufficiency of completeness and correctness of DNA repair would otherwise trigger apoptosis. Based on the aforementioned model, we used embryo culture, inverted microscope, BrdU incorporation and immunofluorescence to explore the cell cycle phase that arrest occurred and the underlying DNA-damage checkpoint pathway in mouse zygotes fertilized with H2O2-treated sperm. We also adopted Tunel to investigate the apoptosis of mouse embryos similarly fertilized at different developmental stages to testify the completeness and correctness of sperm-derived DNA-damage repair. We found G2/M cell cycle arrest in zygotes fertilized with H2O2-treated sperm. ATM (pSer-1981) and Chk1 (pSer-345) activations, rather than ATR (pSer-428) and Chk2 (pThr-68), were detected in zygotes of the treated group. The apoptosis of embryos of different developmental stages of the treated group weren’t different from those of the untreated group. In conclusions, ATM (pSer-1981)-Chk1 (pSer-345) cascade might have mediated G2/M cell cycle arrest and allowed time to facilitate sperm-derived DNA-damage repair in mouse zygotes fertilized with oxygen-stressed sperm, and the DNA-damage repair might be effective.
PMCID: PMC3769350  PMID: 24040138
5.  Dystonia, facial dysmorphism, intellectual disability and breast cancer associated with a chromosome 13q34 duplication and overexpression of TFDP1: case report 
BMC Medical Genetics  2013;14:70.
Dystonia is a movement disorder characterized by involuntary sustained muscle contractions causing twisting and repetitive movements or abnormal postures. Some cases of primary and neurodegenerative dystonia have been associated with mutations in individual genes critical to the G1-S checkpoint pathway (THAP1, ATM, CIZ1 and TAF1). Secondary dystonia is also a relatively common clinical sign in many neurogenetic disorders. However, the contribution of structural variation in the genome to the etiopathogenesis of dystonia remains largely unexplored.
Case presentation
Cytogenetic analyses with the Affymetrix Genome-Wide Human SNP Array 6.0 identified a chromosome 13q34 duplication in a 36 year-old female with global developmental delay, facial dysmorphism, tall stature, breast cancer and dystonia, and her neurologically-normal father. Dystonia improved with bilateral globus pallidus interna (GPi) deep brain stimulation (DBS). Genomic breakpoint analysis, quantitative PCR (qPCR) and leukocyte gene expression were used to characterize the structural variant. The 218,345 bp duplication was found to include ADPRHL1, DCUN1D2, and TMCO3, and a 69 bp fragment from a long terminal repeat (LTR) located within Intron 3 of TFDP1. The 3' breakpoint was located within Exon 1 of a TFDP1 long non-coding RNA (NR_026580.1). In the affected subject and her father, gene expression was higher for all three genes located within the duplication. However, in comparison to her father, mother and neurologically-normal controls, the affected subject also showed marked overexpression (2×) of the transcription factor TFDP1 (NM_007111.4). Whole-exome sequencing identified an SGCE variant (c.1295G > A, p.Ser432His) that could possibly have contributed to the development of dystonia in the proband. No pathogenic mutations were identified in BRCA1 or BRCA2.
Overexpression of TFDP1 has been associated with breast cancer and may also be linked to the tall stature, dysmorphism and dystonia seen in our patient.
PMCID: PMC3722009  PMID: 23849371
Dystonia; Chromosome 13q34; Duplication; TFDP1; Breast cancer; G1-S Checkpoint pathway
6.  Genotype-phenotype correlations in THAP1 dystonia: molecular foundations and description of new cases 
Parkinsonism & related disorders  2012;18(5):414-425.
An extensive variety of THAP1 sequence variants have been associated with focal, segmental and generalized dystonia with age of onset ranging from 3 to over 60 years. In previous work, we screened 1,114 subjects with mainly adult-onset primary dystonia (Neurology 2010;74:229-238) and identified 6 missense mutations in THAP1. For this report, we screened 750 additional subjects for mutations in coding regions of THAP1 and interrogated all published descriptions of THAP1 phenotypes (gender, age of onset, anatomical distribution of dystonia, family history and site of onset) to explore the possibility of THAP1 genotype-phenotype correlations and facilitate a deeper understanding of THAP1 pathobiology. We identified 5 additional missense mutations in THAP1 (p.A7D, p.K16E, p.S21C, p.R29Q, and p.I80V). Three of these variants are associated with appendicular tremors, which were an isolated or presenting sign in some of the affected subjects. Abductor laryngeal dystonia and mild blepharospasm can be manifestations of THAP1 mutations in some individuals. Overall, mean age of onset for THAP1 dystonia is 16.8 years and the most common sites of onset are the arm and neck, and the most frequently affected anatomical site is the neck. In addition, over half of patients exhibit either cranial or laryngeal involvement. Protein truncating mutations and missense mutations within the THAP domain of THAP1 tend to manifest at an earlier age and exhibit more extensive anatomical distributions than mutations localized to other regions of THAP1.
PMCID: PMC3358360  PMID: 22377579
Dystonia; THAP1; DYT6; Spasmodic dysphonia; Tremor
7.  JPH3 Repeat Expansions Cause a Progressive Akinetic-Rigid Syndrome with Severe Dementia and Putaminal Rim in a Five-Generation African-American Family 
Neurogenetics  2012;13(2):133-140.
We report the clinical, neuropsychological, genetic and radiological features of a large five-generation African-American kindred from the southern United States presenting with a progressive akinetic-rigid syndrome and severe dementia, but clinically insignificant chorea, due to mutations in JPH3. Overt disease onset was in the mid-twenties to late thirties with cognitive decline, REM sleep disturbance or psychiatric features, followed by development of a levodopa-unresponsive akinetic-rigid motor syndrome. Dystonia and myoclonus were present in some subjects. A bedridden, non-verbal severely akinetic-rigid state developed within 10 to 15 years after onset. CTG repeat expansions ranged from 47 to 53. Imaging revealed generalized cerebral atrophy with severe striatal involvement and putaminal rim hyperintensity. Analysis of our kindred indicates that JPH3 mutations should be considered in the differential diagnosis of early-onset dementia and hypokinetic-rigid syndromes in individuals of African descent. Moreover, chorea may not be overtly manifest at presentation or during significant parts of the disease course.
PMCID: PMC3370891  PMID: 22447335
Dementia; Parkinsonism; Chorea; Huntington disease; JPH3; Putaminal Rim; African-American
8.  Mutations in CIZ1 cause adult-onset primary cervical dystonia 
Annals of Neurology  2012;71(4):458-469.
Primary dystonia is usually of adult onset, can be familial, and frequently involves the cervical musculature. Our goal was to identify the causal mutation in a family with adult-onset, primary cervical dystonia.
Linkage and haplotype analyses were combined with solution-based whole-exome capture and massively parallel sequencing in a large Caucasian pedigree with adult-onset, primary cervical dystonia to identify a cosegregating mutation. High-throughput screening and Sanger sequencing were completed in 308 Caucasians with familial or sporadic adult-onset cervical dystonia and matching controls for sequence variants in this mutant gene.
Exome sequencing led to the identification of an exonic splicing enhancer mutation in Exon 7 of CIZ1 (c.790A>G, p.S264G) which encodes CIZ1, Cip1-interacting zinc finger protein 1. CIZ1 is a p21Cip1/Waf1-interacting zinc finger protein expressed in brain and involved in DNA synthesis and cell-cycle control. Using a minigene assay, we showed that c.790A>G altered CIZ1 splicing patterns. The p.S264G mutation also altered the nuclear localization of CIZ1. Screening in subjects with adult-onset cervical dystonia identified two additional CIZ1 missense mutations (p.P47S and p.R672M).
Mutations in CIZ1 may cause adult-onset, primary cervical dystonia, possibly by precipitating neurodevelopmental abnormalities that manifest in adults and/or G1/S cell-cycle dysregulation in the mature central nervous system.
PMCID: PMC3334472  PMID: 22447717
9.  Novel PRRT2 mutation in an African-American family with paroxysmal kinesigenic dyskinesia 
BMC Neurology  2012;12:93.
Recently, heterozygous mutations in PRRT2 (Chr 16p11.2) have been identified in Han Chinese, Japanese and Caucasians with paroxysmal kinesigenic dyskinesia. In previous work, a paroxysmal kinesigenic dyskinesia locus was mapped to Chr 16p11.2 - q11.2 in a multiplex African-American family.
Sanger sequencing was used to analyze all four PRRT2 exons for sequence variants in 13 probands (9 Caucasian, 1 Caucasian-Thai, 1 Vietnamese and 2 African-American) with some form of paroxysmal dyskinesia.
One patient of mixed Caucasian-Thai background and one African-American family harbored the previously described hotspot mutation in PRRT2 (c.649dupC, p.R217Pfs*8). Another African-American family was found to have a novel mutation (c.776dupG, p.E260*). Both of these variants are likely to cause loss-of-function via nonsense-mediated decay of mutant PRRT2 transcripts. All affected individuals had classic paroxysmal kinesigenic dyskinesia phenotypes.
Heterozygous PRRT2 gene mutations also cause paroxysmal kinesigenic dyskinesia in African-Americans. The c.649dupC hotspot mutation in PRRT2 is common across racial groups.
PMCID: PMC3460747  PMID: 22985072
PKD; PRRT2; African-American; ICCA; Hotspot mutation
10.  An African-American Family with Dystonia 
Parkinsonism & related disorders  2011;17(7):547-550.
The genetic cause of late-onset focal and segmental dystonia remains unknown in most individuals. Recently, mutations in Thanatos-associated protein domain containing, apoptosis associated protein 1 (THAP1) have been described in DYT6 dystonia and associated with some cases of familial and sporadic late-onset dystonia in Caucasians. We are not aware of any previous descriptions of familial dystonia in African Americans or reports of THAP1 mutations in African Americans. Herein, we characterize an African-American (AA) kindred with late-onset primary dystonia, clinically and genetically. The clinical phenotype included cervical, laryngeal and hand-forearm dystonia. Symptoms were severe and disabling for several family members, whereas others only displayed mild signs. There were no accompanying motor or cognitive signs. In this kindred, age of onset ranged from 45 to 50 years and onset was frequently sudden, with symptoms developing within weeks or months. DYT1 was excluded as the cause of dystonia in this kindred. The entire genomic region of THAP1, including non-coding regions, was sequenced. We identified 13 sequence variants in THAP1, although none co-segregated with dystonia. A novel THAP1 variant (c.-237-3G>T/A) was found in 3/84 AA dystonia patient alleles and 3/212 AA control alleles, but not in 5,870 Caucasian alleles. In summary, although previously unreported, familial primary dystonia does occur in African Americans. Genetic analysis of the entire genomic region of THAP1 revealed a novel variant that was specific for African Americans. Therefore, genetic testing for dystonia and future studies of candidate genes must take genetic background into consideration.
PMCID: PMC3137742  PMID: 21601506
Dystonia; Genetics; African American; DYT6; THAP1; Adult-Onset Dystonias; Dystonia, Hereditary; Focal Dystonia
11.  Effects of the Insemination of Hydrogen Peroxide-Treated Epididymal Mouse Spermatozoa on γH2AX Repair and Embryo Development 
PLoS ONE  2012;7(6):e38742.
Cryopreservation of human semen for assisted reproduction is complicated by cryodamage to spermatozoa caused by excessive reactive oxygen species (ROS) generation.
Methods and Findings
We used exogenous ROS (H2O2) to simulate cryopreservation and examined DNA damage repair in embryos fertilized with sperm with H2O2-induced DNA damage. Sperm samples were collected from epididymis of adult male KM mice and treated with capacitation medium (containing 0, 0.1, 0.5 and 1 mM H2O2) or cryopreservation. The model of DNA-damaged sperm was based on sperm motility, viability and the expression of γH2AX, the DNA damage-repair marker. We examined fertility rate, development, cell cleavage, and γH2AX level in embryos fertilized with DNA-damaged sperm. Cryopreservation and 1-mM H2O2 treatment produced similar DNA damage. Most of the one- and two-cell embryos fertilized with DNA-damaged sperm showed a delay in cleavage before the blastocyst stage. Immunocytochemistry revealed γH2AX in the one- and four-cell embryos.
γH2AX may be involved in repair of preimplantation embryos fertilized with oxygen-stressed spermatozoa.
PMCID: PMC3383764  PMID: 22745678
12.  The c.-237_236GA>TT THAP1 Sequence Variant Does Not Increase Risk for Primary Dystonia 
Sequence variants in coding and non-coding regions of THAP1 have been associated with primary dystonia. In this study, 1446 Caucasian subjects with mainly adult-onset primary dystonia and 1520 controls were genotyped for a variant located in the 5’-untranslated region of THAP1 (c.-237_236GA>TT). Minor allele frequencies were 62/2892 (2.14%) and 55/3040 (1.81%) in subjects with dystonia and controls, respectively (P = 0.202). Subgroup analyses by gender and anatomical distribution also failed to attain statistical significance. In addition, there was no effect of the TT variant on expression levels of THAP1 transcript or protein. Our findings indicate that the c.-237_236GA>TT THAP1 sequence variant does not increase risk for adult-onset primary dystonia in Caucasians.
PMCID: PMC3171986  PMID: 21370264
dystonia; DYT6; high-resolution melting; untranslated region; THAP1
13.  Glial Elements Contribute to Stress-induced Torsina Expression in the Central and Peripheral Nervous Systems 
Neuroscience  2008;155(2):439-453.
DYT1 dystonia is caused by a single GAG deletion in Exon 5 of TOR1A, the gene encoding torsinA, a putative chaperone protein. In this study, central and peripheral nervous system perturbations (transient forebrain ischemia and sciatic nerve transection, respectively) were used to examine the systems biology of torsinA. After forebrain ischemia, quantitative real-time RT-PCR identified increased torsinA transcript levels in hippocampus, cerebral cortex, thalamus, striatum, and cerebellum at 24 h and 7 d. Expression declined toward sham values by 14 d in striatum, thalamus and cortex, and by 21 d in cerebellum and hippocampus. TorsinA transcripts were localized to dentate granule cells and pyramidal neurons in control hippocampus and were moderately elevated in these cell populations at 24 h after ischemia, after which CA1 expression was reduced, consistent with the loss of this vulnerable neuronal population. Increased in situ hybridization signal in CA1 stratum radiatum, stratum lacunosum-moleculare, and stratum oriens at 7 d after ischemia was correlated with the detection of torsinA immunoreactivity in interneurons and reactive astrocytes at 7 and 14 days. Sciatic nerve transection increased torsinA transcript levels between 24 h and 7 days in both ipsilateral and contralateral dorsal root ganglia (DRG). However, increased torsinA immunoreactivity was localized to both ganglion cells and satellite cells in ipsilateral DRG but was restricted to satellite cells contralaterally. These results suggest that torsinA participates in the response of neural tissue to central and peripheral insults and its sustained up-regulation indicates that torsinA may contribute to remodeling of neuronal circuitry. The striking induction of torsinA in astrocytes and satellite cells points to the potential involvement of glial elements in the pathobiology of DYT1 dystonia.
PMCID: PMC2596935  PMID: 18538941
DYT1; dystonia; reactive astrocytes; hippocampus; satellite cells; dorsal root ganglia
14.  High-throughput mutational analysis of TOR1A in primary dystonia 
BMC Medical Genetics  2009;10:24.
Although the c.904_906delGAG mutation in Exon 5 of TOR1A typically manifests as early-onset generalized dystonia, DYT1 dystonia is genetically and clinically heterogeneous. Recently, another Exon 5 mutation (c.863G>A) has been associated with early-onset generalized dystonia and some ΔGAG mutation carriers present with late-onset focal dystonia. The aim of this study was to identify TOR1A Exon 5 mutations in a large cohort of subjects with mainly non-generalized primary dystonia.
High resolution melting (HRM) was used to examine the entire TOR1A Exon 5 coding sequence in 1014 subjects with primary dystonia (422 spasmodic dysphonia, 285 cervical dystonia, 67 blepharospasm, 41 writer's cramp, 16 oromandibular dystonia, 38 other primary focal dystonia, 112 segmental dystonia, 16 multifocal dystonia, and 17 generalized dystonia) and 250 controls (150 neurologically normal and 100 with other movement disorders). Diagnostic sensitivity and specificity were evaluated in an additional 8 subjects with known ΔGAG DYT1 dystonia and 88 subjects with ΔGAG-negative dystonia.
HRM of TOR1A Exon 5 showed high (100%) diagnostic sensitivity and specificity. HRM was rapid and economical. HRM reliably differentiated the TOR1A ΔGAG and c.863G>A mutations. Melting curves were normal in 250/250 controls and 1012/1014 subjects with primary dystonia. The two subjects with shifted melting curves were found to harbor the classic ΔGAG deletion: 1) a non-Jewish Caucasian female with childhood-onset multifocal dystonia and 2) an Ashkenazi Jewish female with adolescent-onset spasmodic dysphonia.
First, HRM is an inexpensive, diagnostically sensitive and specific, high-throughput method for mutation discovery. Second, Exon 5 mutations in TOR1A are rarely associated with non-generalized primary dystonia.
PMCID: PMC2661056  PMID: 19284587
15.  Caytaxin Deficiency Disrupts Signaling Pathways in Cerebellar Cortex 
Neuroscience  2006;144(2):439-461.
The genetically dystonic (dt) rat, an autosomal recessive model of generalized dystonia, harbors an insertional mutation in Atcay. As a result, dt rats are deficient in Atcay transcript and the neuronally-restricted protein caytaxin. Previous electrophysiological and biochemical studies have defined olivocerebellar pathways, particularly the climbing fiber projection to Purkinje cells, as a site of significant functional abnormality in dt rats. In normal rats, Atcay transcript is abundantly expressed in the granular and Purkinje cell layers of cerebellar cortex. To better understand the consequences of caytaxin deficiency in cerebellar cortex, differential gene expression was examined in dt rats and their normal littermates. Data from oligonucleotide microarrays and quantitative real-time RT-PCR (QRT-PCR) identified phosphatidylinositol signaling pathways, calcium homeostasis, and extracellular matrix interactions as domains of cellular dysfunction in dt rats. In dt rats, genes encoding the corticotropin-releasing hormone receptor 1 (CRH-R1, Crhr1) and calcium-transporting plasma membrane ATPase 4 (PMCA4, Atp2b4) showed the greatest up-regulation with QRT-PCR. Immunocytochemical experiments demonstrated that CRH-R1, CRH, and PMCA4 were up-regulated in cerebellar cortex of mutant rats. Along with previous electrophysiological and pharmacological studies, our data indicate that caytaxin plays a critical role in the molecular response of Purkinje cells to climbing fiber input. Caytaxin may also contribute to maturational events in cerebellar cortex.
PMCID: PMC1868412  PMID: 17092653

Results 1-15 (15)