Mutations in the NKX2.1 gene, which is essential for the development, differentiation and organization of the basal ganglia, cause benign hereditary chorea (BHC) characterized by childhood-onset non-progressive chorea. We herein report the clinical features of six patients from a single family with a novel intronic mutation and present the dopaminergic neuronal imaging by using positron emission tomography (PET) imaging to assess the integrity of the striatal dopaminergic system using [(11)C]-CFT for the presynaptic dopamine transporter function and [(11)C]-raclopride for the postsynaptic D2 receptor function. The patients showed mild generalized chorea without either congenital hypothyroidism or a history of pulmonary infection and some of the patients had goiter. Genetic analyses of NKX2.1 gene showed a novel heterozygous c.464-9C>A mutation that created a new acceptor splice site resulting in the production of an aberrant transcript with a 7-bp insertion identical to a intronic sequence of genomic DNA. Oral levodopa failed to improve the involuntary movement, while haloperidol, a dopamine D2 receptor blocking agent, exacerbated the choric movement in a single patient. The dopaminergic PET studies in the two patients revealed decreased raclopride binding in the striatum, while the CFT binding was not altered. The impairment of D2 receptor function in the basal ganglia may result in exacerbation of the chorea induced by haloperidol. The molecular brain imaging and therapeutic response may help elucidate the pathophysiological mechanism of the motor control in the BHC-associated NKX2.1 mutation.

BackgroundCongenital 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 AVPR2 locus and approximately half of the Rho GTPase-activating protein 4 (ARHGAP4) 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.ARHGAP4 is expressed at high levels in hematopoietic cells, and it has been reported that an NDI patient lacking AVPR2 and all of ARHGAP4 showed immunodeficiency characterised by a marked reduction in the number of circulating CD3+ cells and almost complete absence of CD8+ cells.MethodsPCR 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.ResultsWe evaluated subjects (one child and two adults) with 11.2-kb deletion that includes the entire AVPR2 locus and approximately half of the ARHGAP4. 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 ARHGAP4 revealed that expression of RhoGAP family genes was not influenced greatly by the lack of ARHGAP4.ConclusionThese results suggest that loss of ARHGAP4 expression is not compensated for by other family members. ARHGAP4 may play some role in lymphocyte differentiation but partial loss of ARHGAP4 does not result in clinical immunodeficiency.

Background: 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.

A 23-year-old manwas recognized as a sporadic case offacioscapulohumeral syndrome(FSH syndrome). Hewas a case of early onset, and there was severe atrophy of skeletal muscles, although muscle biopsy was normal. Electromyogram revealed neurogenic changes. This patient also had severe sensorineural hearing loss and a mild abnormality of retinal vessels. It is known that some FSHdystrophy or FSHspinal muscular atrophy patients have such coincidental complications. The cause of these coincidences is still unclear, but their occurrence suggests the pleiotropy of the FSH syndrome. (Internal Medicine 32: 678-680, 1993)

BackgroundSystemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis and composed of two subtypes, limited and diffuse cutaneous forms. Previous genetic studies including genome-wide association studies (GWAS) have identified 12 susceptibility loci satisfying genome-wide significance.ObjectivesTo expand the list of susceptibility genes and deepen biological insights for SSc.MethodsWe performed trans-ethnic meta-analysis of GWAS in the Japanese and European populations, followed by a two-staged replication study comprising a total of 4,436 cases and 14,751 controls. Associations between significant single nuclear polymorphisms (SNPs) and neighboring genes were evaluated. Enrichment analysis of H3K4Me3, a representative histone mark for active promoter was conducted with an expanded list of SSc susceptibility genes.ResultsWe identified two significant SNP in two loci, GSDMA and PRDM1, both of which are related with immune functions and associated with other autoimmune diseases (p=1.4x10-10 and 6.6x10-10, respectively). GSDMA also showed a significant association with limited cutaneous SSc. We also replicated the associations of previously reported loci including a non-GWAS locus, TNFAIP3. PRDM1 encodes BLIMP1, a transcription factor regulating T cell proliferation and plasma cell differentiation. The top SNP in GSDMA was a missense variant and correlated with gene expression of neighboring genes, and this could explain the association in this locus. We found different HLA association patterns between the two populations or two subtypes. Enrichment analysis suggested the importance of CD4 naïve primary T cell.Conclusions GSDMA and PRDM1 are associated with SSc. These findings provide enhanced insight into the genetic and biological basis of SSc.Disclosure of InterestNone declared