A Novel Mutation (Q694X) in the ITGB3 Gene Causing Glanzmann’s Thrombasthenia from the Sultanate of Oman

Background: Glanzmann Thrombasthenia (GT) results from mutations in the genes ITGA2B and ITGB3, located on chromosome 17q21–23 which encodes the platelet glycoprotein αIIbβ3 complex, namely GPIIb (αIIb) and GPIIIa (β3), the fibrinogen receptors on platelets, which play an important role in platelet aggregation. Patients with GT can require frequent hospitalization and can be a burden on the nation’s health resources. The possibility that GT could be cured by gene replacement therapy makes it essential to study the molecular basis of the GT patients in a particular family or kindred. Objectives: Our aim was to identify the underlying mutations responsible for GT in Omani patients in order to establish a strategy for genetic counseling and carrier detection to prevent the occurrence of the homozygous state by prenatal diagnosis. Methods: GT was diagnosed in a 17 year old Omani female at the Sultan Qaboos University Hospital. The diagnosis of GT was based on clinical features, platelet aggregometry and biochemical studies. Platelet surface expression of GPIIb/IIIa was also studied by flowcytometry. Molecular studies performed at Medical Genetics Department, Tsukuba University, Japan, include DNA sequencing of all exons and exon-intron junctions of ITGA2B and ITGB3 of the two genes by the ABI 3100 Genetic Analyzer®. [Applied Biosystems, Foster City, CA, USA]. Genomic DNA was also analyzed by Illumina Human-1 Bead Chip Illumina® (Illumina Inc., San Diego, CA, USA) to exclude the whole region of the two genes that could produce an apparent homozygous state. Results: We have identified a novel nonsense causative mutation (Q694X) by sequencing the ITGB3 gene. [Figure 1a & b]. In addition, sequencing ITGB3 gene also revealed 2 SNPs (rs 3809863; IVS14+9C/T, rs 3809865; 3383T/A). The Micro-Array assay using Illumina Human-1 Bead chip excluded the possibility of deletion of these genes in chromosome 17 in this patient. Summary/Conclusion: A stop codon was found in exon 13 of ITGB3 gene causing the translated protein to be abnormally shortened. It is hypothesized that the altered form of ITGB3 gene is both extremely unstable and rapidly degraded after its biosynthesis, leading to a loss of function of the protein. Further RNA expression studies, transfection tests and cDNA sequencing are ongoing to elucidate the molecular mechanisms responsible for GT

A case report of de novo missense FOXP1 mutation in a non-Caucasian patient with global developmental delay and severe speech impairment

The FOXP protein family (FOXP1-4) is a group of transcription factors that play important roles in embryological, immunological, hematological, and speech and language development. Here, we report FOXP1 de novo mutation and severe speech delay in an individual belonging to a non-Caucasian population

Large scale genotyping study for asthma in the Japanese population

<p>Abstract</p> <p>Background</p> <p>Asthma is a complex phenotype that is influenced by both genetic and environmental factors. Genome-wide linkage and association studies have been performed to identify susceptibility genes for asthma. These studies identified new genes and pathways implicated in this disease, many of which were previously unknown.</p> <p>Objective</p> <p>To perform a large-scale genotyping study to identify asthma-susceptibility genes in the Japanese population.</p> <p>Methods</p> <p>We performed a large-scale, three-stage association study on 288 atopic asthmatics and 1032 controls, by using multiplex PCR-Invader assay methods at 82,935 single nucleotide polymorphisms (SNPs) (1^ststage). SNPs that were strongly associated with asthma were further genotyped in samples from asthmatic families (216 families, 762 members, 2^ndstage), 541 independent patients, and 744 controls (3^rdstage).</p> <p>Results</p> <p>SNPs located in the 5' region of <it>PEX19 </it>(rs2820421) were significantly associated with <it>P </it>< 0.05 through the 1^stto the 3^rdstage analyses; however, the <it>P </it>values did not reach statistically significant levels (combined, <it>P </it>= 3.8 × 10^-5; statistically significant levels with Bonferroni correction, <it>P </it>= 6.57 × 10^-7). SNPs on <it>HPCAL1 </it>(rs3771140) and on <it>IL18R1 </it>(rs3213733) were associated with asthma in the 1^stand 2^ndstage analyses, but the associations were not observed in the 3^rdstage analysis.</p> <p>Conclusion</p> <p>No association attained genome-wide significance, but several loci for possible association emerged. Future studies are required to validate these results for the prevention and treatment of asthma.</p

Immunological profile in a family with nephrogenic diabetes insipidus with a novel 11 kb deletion in AVPR2 and ARHGAP4 genes

<p>Abstract</p> <p>Background</p> <p>Congenital nephrogenic diabetes insipidus (NDI) is characterised by an inability to concentrate urine despite normal or elevated plasma levels of the antidiuretic hormone arginine vasopressin. We report a Japanese extended family with NDI caused by an 11.2-kb deletion that includes the entire <it>AVPR2 </it>locus and approximately half of the <it>Rho GTPase-activating protein 4 </it>(<it>ARHGAP4</it>) locus. ARHGAP4 belongs to the RhoGAP family, Rho GTPases are critical regulators of many cellular activities, such as motility and proliferation which enhances intrinsic GTPase activity.</p> <p>ARHGAP4 is expressed at high levels in hematopoietic cells, and it has been reported that an NDI patient lacking <it>AVPR2 </it>and all of <it>ARHGAP4 </it>showed immunodeficiency characterised by a marked reduction in the number of circulating CD3+ cells and almost complete absence of CD8+ cells.</p> <p>Methods</p> <p>PCR and sequencing were performed to identify the deleted region in the Japanese NDI patients. Immunological profiles of the NDI patients were analysed by flow cytometry. We also investigated the gene expression profiles of peripheral blood mononuclear cells (PBMC) from NDI patients and healthy controls in microarray technique.</p> <p>Results</p> <p>We evaluated subjects (one child and two adults) with 11.2-kb deletion that includes the entire <it>AVPR2 </it>locus and approximately half of the <it>ARHGAP4</it>. Hematologic tests showed a reduction of CD4+ cells in one adult patient, a reduction in CD8+ cells in the paediatric patient, and a slight reduction in the serum IgG levels in the adult patients, but none of them showed susceptibility to infection. Gene expression profiling of PBMC lacking <it>ARHGAP4 </it>revealed that expression of RhoGAP family genes was not influenced greatly by the lack of <it>ARHGAP4</it>.</p> <p>Conclusion</p> <p>These results suggest that loss of <it>ARHGAP4 </it>expression is not compensated for by other family members. ARHGAP4 may play some role in lymphocyte differentiation but partial loss of <it>ARHGAP4 </it>does not result in clinical immunodeficiency.</p

Role of STAT4 polymorphisms in systemic lupus erythematosus in a Japanese population: a case-control association study of the STAT1-STAT4 region

IntroductionRecent studies identified STAT4 (signal transducers and activators of transcription-4) as a susceptibility gene for systemic lupus erythematosus (SLE). STAT1 is encoded adjacently to STAT4 on 2q32.2-q32.3, upregulated in peripheral blood mononuclear cells from SLE patients, and functionally relevant to SLE. This study was conducted to test whether STAT4 is associated with SLE in a Japanese population also, to identify the risk haplotype, and to examine the potential genetic contribution of STAT1. To accomplish these aims, we carried out a comprehensive association analysis of 52 tag single nucleotide polymorphisms (SNPs) encompassing the STAT1-STAT4 region.MethodsIn the first screening, 52 tag SNPs were selected based on HapMap Phase II JPT (Japanese in Tokyo, Japan) data, and case-control association analysis was carried out on 105 Japanese female patients with SLE and 102 female controls. For associated SNPs, additional cases and controls were genotyped and association was analyzed using 308 SLE patients and 306 controls. Estimation of haplotype frequencies and an association study using the permutation test were performed with Haploview version 4.0 software. Population attributable risk percentage was estimated to compare the epidemiological significance of the risk genotype among populations.ResultsIn the first screening, rs7574865, rs11889341, and rs10168266 in STAT4 were most significantly associated (P < 0.01). Significant association was not observed for STAT1. Subsequent association studies of the three SNPs using 308 SLE patients and 306 controls confirmed a strong association of the rs7574865T allele (SLE patients: 46.3%, controls: 33.5%, P = 4.9 × 10-6, odds ratio 1.71) as well as TTT haplotype (rs10168266/rs11889341/rs7574865) (P = 1.5 × 10-6). The association was stronger in subgroups of SLE with nephritis and anti-double-stranded DNA antibodies. Population attributable risk percentage was estimated to be higher in the Japanese population (40.2%) than in Americans of European descent (19.5%).ConclusionsThe same STAT4 risk allele is associated with SLE in Caucasian and Japanese populations. Evidence for a role of STAT1 in genetic susceptibility to SLE was not detected. The contribution of STAT4 for the genetic background of SLE may be greater in the Japanese population than in Americans of European descent

Single nucleotide polymorphism-based genome-wide linkage analysis in Japanese atopic dermatitis families

<p>Abstract</p> <p>Background</p> <p>Atopic dermatitis develops as a result of complex interactions between several genetic and environmental factors. To date, 4 genome-wide linkage studies of atopic dermatitis have been performed in Caucasian populations, however, similar studies have not been done in Asian populations. The aim of this study was to identify chromosome regions linked to atopic dermatitis in a Japanese population.</p> <p>Methods</p> <p>We used a high-density, single nucleotide polymorphism genotyping assay, the Illumina BeadArray Linkage Mapping Panel (version 4) comprising 5,861 single nucleotide polymorphisms, to perform a genome-wide linkage analysis of 77 Japanese families with 111 affected sib-pairs with atopic dermatitis.</p> <p>Results</p> <p>We found suggestive evidence for linkage with 15q21 (LOD = 2.01, NPL = 2.87, <it>P </it>= .0012) and weak linkage to 1q24 (LOD = 1.26, NPL = 2.44, <it>P </it>= .008).</p> <p>Conclusion</p> <p>We report the first genome-wide linkage study of atopic dermatitis in an Asian population, and novel loci on chromosomes 15q21 and 1q24 linked to atopic dermatitis. Identification of novel causative genes for atopic dermatitis will advance our understanding of the pathogenesis of atopic dermatitis.</p

Brain Neuronal CB2 Cannabinoid Receptors in Drug Abuse and Depression: From Mice to Human Subjects

BACKGROUND: Addiction and major depression are mental health problems associated with stressful events in life with high relapse and reoccurrence even after treatment. Many laboratories were not able to detect the presence of cannabinoid CB2 receptors (CB2-Rs) in healthy brains, but there has been demonstration of CB2-R expression in rat microglial cells and other brain associated cells during inflammation. Therefore, neuronal expression of CB2-Rs had been ambiguous and controversial and its role in depression and substance abuse is unknown. METHODOLOGY/PRINCIPAL FINDINGS: In this study we tested the hypothesis that genetic variants of CB2 gene might be associated with depression in a human population and that alteration in CB2 gene expression may be involved in the effects of abused substances including opiates, cocaine and ethanol in rodents. Here we demonstrate that a high incidence of (Q63R) but not (H316Y) polymorphism in the CB2 gene was found in Japanese depressed subjects. CB2-Rs and their gene transcripts are expressed in the brains of naïve mice and are modulated following exposure to stressors and administration of abused drugs. Mice that developed alcohol preference had reduced CB2 gene expression and chronic treatment with JWH015 a putative CB2-R agonist, enhanced alcohol consumption in stressed but not in control mice. The direct intracerebroventricular microinjection of CB2 anti-sense oligonucleotide into the mouse brain reduced mouse aversions in the plus-maze test, indicating the functional presence of CB2-Rs in the brain that modifies behavior. We report for the using electron microscopy the sub cellular localization of CB2-Rs that are mainly on post-synaptic elements in rodent brain. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate the functional expression of CB2-Rs in brain that may provide novel targets for the effects of cannabinoids in depression and substance abuse disorders beyond neuro-immunocannabinoid activity