The fragile X-associated tremor ataxia syndrome (FXTAS) in Indonesia

Fragile X-associated disorders caused by the premutation of the FMR1 gene, includes the fragile X-associated tremor/ataxia syndrome (FXTAS). FXTAS affects more than 40% of premutation males over the age of 50 and 75% over the age of 80. FMR1 molecular analysis was done using PCR and confirmed by Southern Blot. Three premutation males were diagnosed FXTAS using quantification based on the standard neurological examination. Cognitive impairment was assessed using Raven and WAIS-R test. MRI was done to identify the middle cerebellar peduncle (MCP) sign, white matter disease and/or cerebral atrophy. Three cases of FXTAS are identified, of five individuals older than 50 years in one family tree two met criteria for definite FXTAS and the third with sub-clinical symptoms, although cognitive and radiological criteria are met. These cases are the first identified FXTAS cases in rural Indonesia. In addition with lack of routine medical follow-up, complications of FXTAS, such as hypertension may go unrecognized and untreated, which may further exacerbate the central nervous system (CNS) findings of FXTAS

An Improved RSP Method to Detect HpaI Polymorphism in the Apolipoprotein C-1 Gene Promoter

BACKGROUND: An apolipoprotein C1 gene promoter polymorphism (CGTT insertion at position -317) is associated with familial dysbetalipoprotemia, cardiovascular diseases, and Alzheimer's disease. Restriction site polymorphism (RSP) assays were previously established to detect this polymorphism. In this study, we introduce an improved RSP assay to detect this polymorphism. METHODS: This method included newly designed primers and only one round of PCR amplification which yields one short and specific APOC1 fragment followed by HpaI digestion. Briefly, It consists of three steps: 1) one round of PCR amplification of DNA sample, 2) HpaI enzyme digestion of PCR products, and 3) electrophoresis on an agarose gel to visualize the genotypes. This improved RSP method was applied to genotype 92 human samples collected from The Johns Hopkins Hospital. RESULTS: The observed allele frequencies for H1 and H2 from 92 genotyped human subjects were 0.707 and 0.293 respectively. The H2 allele frequency in the black subjects (0.350) was significantly (p = 0.024) higher than that in the white subjects (0.177). This method was more economical and convenient than the methods previously reported to detect this mutation in the APOC1 gene. CONCLUSIONS: This assay will be readily applied to screen large sample sizes for population studies in a simple and cost effective way

Molecular analyses in Indonesian individuals with intellectual disability and microcephaly

Background Intellectual disability (ID) often coincides with an abnormal head circumference (HC). Since the HC is a reflection of brain size, abnormalities in HC may be a sign of a brain anomaly. Although microcephaly is often secondary to ID, hereditary (autosomal recessive) forms of primary microcephaly (MCPH) exist that result in ID. Objective To investigate mutations in MCPH genes in patients with ID and microcephaly. Methods From a population of 527 Indonesian individuals with ID, 48 patients with microcephaly (9.1 %) were selected. These patients were previously found to be normal upon conventional karyotyping, fragile X mental retardation 1 (FMRl) gene analysis, subtelomeric deletion, and duplication multiplex ligationdependent probe amplification (MLPA). Sanger sequencing for abnormal spindle-like microcephaly-associated (ASPM) and WD repeat domain 62 (WDR62) was performed in all 48 subjects, while sequencing for microcephalin (MCPHl), cyclin-dependent kinase 5 (CDK5) regulatory subunit-associated protein 2 (CD5KRAP2) , centromere protein} (CENPJ), and SCUfALl interrupting locus (STIL) was conducted in only the subjects with an orbitofrontal cortex (OFC) below -4 SD. Results In all genes investigated, 66 single nucleotide polymorphisms (SNPs) and 15 unclassified variants which were predicted as unlikely to be pathogenic (lN2), were identified. Possible pathogenic variants (lN3) were identified in ASPM. However, since none of the patients harboured compound heterozygous likely pathogenic mutations, no molecular MCPH diagnosis could be established. Interestingly, one of the patients harboured the same variants as her unaffected monozygotic twin sister, indicating that our cohort included a discordant twin. Conclusions This study is the first to investigate for possible genetic causes ofMCPH in the Indonesian population. The absence of causative pathogenic mutations in the MCPH genes tested may originate from several factors. The identification of UV2 and UV3 variants as well as the absence of causative pathogenic mutations calls for further investigations

Analysis of rare variants in the CFH gene in patients with the cuticular drusen subtype of age-related macular degeneration

Purpose: Age-related macular degeneration (AMD) and cuticular drusen (CD), a clinical subtype of AMD, have been linked to genetic variants in the complement factor H (CFH) gene. In this study, we aimed to investigate the frequency of rare variants in the CFH gene in 180 cases with CD. In addition, we aimed to determine the frequency of a previously reported rare, highly penetrant CFH variant (p. Arg1210Cys) in a Dutch-German non-CD-type AMD case-control cohort, and to describe the phenotype of patients carrying the p. Arg1210Cys variant. Methods: Study subjects were selected from the European Genetic Database (EUGENDA), a joint AMD database of the Radboud University Medical Centre and the University Hospital of Cologne, and graded at the Cologne Image Reading Centre and Laboratory (CIRCL). Additionally, two CD cases were recruited from the VU Medical Centre in Amsterdam. The CFH gene was analyzed in 180 CD cases with Sanger sequencing. All identified variants were analyzed for potential damaging effects with prediction software tools Sorting Intolerant from Tolerant (SIFT) and Polymorphism Phenotyping (PolyPhen). In addition, we genotyped the p. Arg1210Cys variant in 813 non-CD type AMD cases and 1175 controls. Results: Sequencing identified 11 rare, heterozygous missense variants, one frameshift variant, and one splice acceptor site variant in 16 CD cases. The p. Arg1210Cys variant was identified in two CD cases but was not identified in our Dutch-German non-CD-type AMD case-control cohort. Conclusions: The present study identified the presence of rare variants in the CFH gene in 16 (8.8%) of 180 patients with the CD subtype of AMD. The carriers of rare CFH variants displayed a significantly earlier age at onset than non-carriers (p=0.016). The rare missense variant p. Arg1210Cys was identified in two CD cases, but was not detected in 813 non-CD type AMD cases or in the 1,175 controls of our Dutch-German cohort. The current study suggests that the p. Arg1210Cys variant may be restricted to a subset of patients with the CD subtype of AMD. Detailed clinical pheno-typing, including fluorescein angiography, of patients with AMD carrying the p. Arg1210Cys variant in other cohorts is required to confirm this finding