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Abstract The fragile X premutation is a public health concern worldwide. Implementing a comprehensive screening program for FMR1 premutation alleles could empower individuals and families with information, supporting informed health decisions and potentially reducing the incidence of fragile X syndrome (FXS). This study aimed to determine the prevalence of FMR1 premutations in the Thai population. We screened 369 female blood donors and 449 males with tremor and/or ataxia who tested negative for spinocerebellar ataxia (SCA) types 1, 2, and 3 for FMR1 CGG repeat expansions. Among the female blood donors, 0.27% (1/369) had a premutation allele, and 1.08% (4/369) had intermediate alleles. One female with a premutation carrier had 89 CGG repeats with one AGG interruption. In the male cohort, no premutations or full mutations were found; however, intermediate alleles were identified in 0.67% (3/449) of the males. This study provides the evidence of fragile X premutation screening in the Thai population. These findings contribute to the understanding of FMR1 premutation prevalence in Thailand and should encourage wider discussions on the feasibility for a national fragile X carrier screening program in Thailand to reduce the burden of fragile X-associated disorders.

Abstract Genetic screening for HLA‐B*15:02 before prescribing carbamazepine is standard practice to prevent severe cutaneous adverse reactions in Asian populations. These reactions are associated not only with this allele but also with closely related HLA‐B75 serotype markers—HLA‐B*15:11 and HLA‐B*15:21—which are prevalent in several Asian countries. However, a reliable method for identifying HLA‐B75 serotype markers is still not available. We developed an in‐house quantitative PCR (qPCR) for HLA‐B75 screening and validated it using 303 anonymized DNA samples. Due to inadequate quality control, the qPCR results for 11 samples were excluded. We analyzed the sensitivity and specificity of the test using 93 HLA‐typed samples. The concordance between the qPCR method and an established screening method was assessed using 199 HLA‐screened samples tested for HLA‐B*15:02 at Songklanagarind Hospital, Songkhla, Thailand. All discordant results were confirmed by Sanger sequencing. The qPCR method demonstrated a sensitivity of 100% (95% confidence interval = 83.16%–100.00%) and a specificity of 100% (95% confidence interval = 95.07%–100.00%). Concordance analysis revealed a 96.5% agreement between methods (192/199; 44 positive and 148 negative results). All discordant results were due to HLA‐B75 markers not being HLA‐B*15:02 (two samples with HLA‐B*15:11 and five samples with HLA‐B*15:21). In conclusion, this qPCR method could be useful for identifying HLA‐B75 carriers at risk of carbamazepine‐induced reactions in Asian populations where carriers of HLA‐B*15:02, HLA‐B*15:11, or HLA‐B*15:21 are common.

Chimerism is a very rare genetic finding in human. Most reported cases have a chi 46,XX/46,XY karyotype. Only three non-twin cases carrying both trisomy 21 and a normal karyotype have been reported, including two cases with a chi 47,XY,+21/46,XX karyotype and a case with a chi 47,XX,+21/46,XY karyotype. Herein we describe an additional case with a chi 47,XY,+21/46,XX karyotype. For the case, a physical examination at the age of 1 year revealed ambiguous genitalia with no features of Down syndrome or other malformations. Growth and developmental milestones were within normal ranges. We performed short tandem repeat (STR) and single nucleotide polymorphism (SNP) microarray analyses to attempt to identify the mechanism underlying the chimerism in this patient and the origin of the extra chromosome 21. Cytogenetic analyses of the patient’s peripheral blood revealed approximately 17% of a 47,XY,+21 lineage by G-banding karyotype analysis, 13%–17% by FISH analyses of uncultured peripheral blood, and 10%–15% by SNP microarray analysis. Four years later, the percentage of trisomy 21 cells had decreased to approximately 6%. SNP microarray and STR analyses revealed a single maternal and double paternal genetic contribution to the patient for the majority of the markers, including the chromosome 21 markers. The extra chromosome 21 was paternally derived and meiosis I nondisjunction likely occurred during spermatogenesis. The mechanisms underlying chimera in our case was likely fertilization two spermatozoa, one with an ovum and the other with the second polar body.

Fragile X (FRAXA) syndrome and fragile XE (FRAXE) syndrome are caused by the expansion of a trinucleotide repeat in the FMR1 and FMR2 genes, respectively. Currently, there are several methods available for fragile X syndrome screening in a large population, however these methods require relatively expensive equipment and have limitations in some laboratory settings. This study developed a multiplex PCR of triplet repeats in FMR1 and FMR2 genes using standard PCR instruments. The new multiplex PCR method was tested in known samples with variable repeat sizes of FMR1 and FMR2 genes to validate the technique and was then applied to prospective index male samples. All the multiplex PCR results matched well results from standard methods. We propose a single‐tube multiplex PCR technique, which is very reliable for rapid screening FMR1 and FMR2 normal and expanded alleles in males for a large cohort study, and can be used in limited-resource settings.

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders which are etiologically heterogeneous. Chromosomal microarray is now recommended as the first-tier clinical diagnostic test for ASD. We performed chromosomal microarray in 16 Thai patients with ASD using an Illumina HumanCytoSNP-12 v2.1 array and found one case with uniparental disomy (UPD) of chromosome 15. Methylation-specific PCR showed abnormal methylation of the maternal SNRPN allele. Haplotype analysis revealed that the patient had received both chromosomes 15 from his father. These results were consistent with Angelman syndrome. However, his clinical features had no clinical significance for classic Angelman syndrome. He had first presented at the pediatric clinic with no speech, poor social interaction skills and repetitive behaviors consistent with ASD based on the DSM-IV criteria at 2 years of age and later confirmed by ADOS at 5 years of age. He was strikingly overweight but had no dysmorphic facies, seizures nor ataxia and was diagnosed as non-syndromic ASD, a diagnosis which was believed until at 10 years of age, his DNA was included for analysis in this current cohort study. Our findings suggest that ASD patients with unknown etiology should be considered for methylation-specific PCR testing for Angelman syndrome where chromosomal microarray is not available. In the study, we also review the clinical features of Angelman syndrome caused by UPD and the frequency of ASD in individuals with Angelman syndrome.

Background and Objectives: Autism spectrum disorder (ASD) is a neurodevelopmental disorder the cause of which is not fully known. Genetic factors are believed to play a major role in the etiology of ASD. However, genetic factors have been identified in only some cases, and other causes remain to be identified. This study aimed to identify potential associations between ASD and the 19-bp insertion/deletion polymorphism in the dopamine beta-hydroxylase (DBH) gene which plays a crucial role in the metabolism of neurotransmitters. Materials and Methods: The 19-bp insertion/deletion polymorphism upstream of the DBH gene was analyzed for associations in 177 ASD patients and 250 healthy controls. Family-based analysis was performed in family trios of each patient using the transmission disequilibrium test to investigate the potential contributions of this DBH polymorphism to ASD. Results: The frequency of the 19-bp insertion allele was significantly higher in the patient group compared to the controls (0.624 vs. 0.556, respectively; p = 0.046). The frequency of the insertion/insertion genotype was also higher in the patient group (0.378 vs. 0.288, respectively) but without statistical significance (p = 0.110). The family-based analysis showed an association between patient families and the insertion allele when only families of male participants were analyzed (73 vs. 48 events; OR 1.521; 95% CI 1.057–2.189; p = 0.023). Conclusions: This population-based analysis found an association between the 19-bp insertion allele of the DBH gene and ASD. No association at the genotype level was found. The family-based analysis found an association between the insertion allele and ASD when the analysis was performed on male participants only, suggesting a linkage between the DBH locus and ASD.

Objectives: Microscopic examination is essential in urine analysis. This is a simple way to collect informative data but it is also labor-intensive, time-consuming, and requires experienced staff for accurate results and interpretation. Several automated urine analyzers have been introduced for urine analysis in medical laboratories. The aim of this study was to assess and compare the performance of the most common three automated urine analyzers, Cobas 6500, UN3000-111b and iRICELL 3000. Methods: A total of 100 routine urine samples were used in the study. Results from the three machines were compared with the routine procedure results including physical, chemical and sediment analysis. Results: There was good correlation of urine physical and chemical analyses between the three analyzers with an overall concordance level of more than 80%. For sediment analysis, the degree of concordance between manual analysis and the three instruments was very good to good for white blood cells, red blood cells and epithelial cells, and moderate for bacteria. There were fair to good agreements between manual microscopy and the three instruments, Cobas 6500, UN3000-111b and iRICELL 3000, for casts (Cohen’s kappa 0.42, 0.38 and 0.62, respectively). Conclusions: The three automated urine analyzers showed similar performances and good correlation with manual microscopy. The results of this study indicate that automated urine analyzers could be used for initial urine testing to reduce high workloads and to save time, but manual microscopic analysis by experienced staff is still necessary to classify urine sediments for confirmation, especially in pathologic specimens.

Autism spectrum disorder (ASD) is a highly heterogeneous neurodevelopmental disorder with many contributing risk genes and loci. To date, several intellectual disability (ID) susceptibility genes have frequently been identified in ASD. Here, whole exome sequencing was carried out on a proband with ASD and identified compound heterozygous mutations of the TRAPPC9, which plays a role in the neuronal NF-κB signaling pathway. These mutations consisted of a novel frameshift mutation (c.2415_2416insC, p.His806Profs∗9) and a rare splice site mutation (c.3349+1G>A) that were segregated from an unaffected father and unaffected mother, respectively. These two heterozygous mutations were also identified in the patient’s older brother with ID. Quantitative RT-PCR revealed a significant reduction of TRAPPC9 transcript in two siblings. This study first describes compound heterozygous mutations of the TRAPPC9 gene in two siblings with ASD and ID, which is notable as only homozygous mutations or compound heterozygous for copy number variations and rare variant in this gene have been reported to date and associated with autosomal recessive intellectual disability. The two siblings carrying compound heterozygous TRAPPC9 mutations presented with ID, developmental delay, microcephaly and brain abnormalities similarly to the clinical features found in almost cases with homozygous TRAPPC9 mutation in previous studies. Together this study provides evidence that clinical manifestations of TRAPPC9 mutations as seen in our patients with ID and autism may be broader than previous case reports have indicated.

Autism spectrum disorder (ASD) has a strong genetic basis, although the genetics of autism is complex and it is unclear. Genetic testing such as microarray or sequencing was widely used to identify autism markers, but they are unsuccessful in several cases. The objective of this study is to identify causative variants of autism in two Thai families by using whole-exome sequencing technique. Whole-exome sequencing was performed with autism-affected children from two unrelated families. Each sample was sequenced on SOLiD 5500xl Genetic Analyzer system followed by combined bioinformatics pipeline including annotation and filtering process to identify candidate variants. Candidate variants were validated, and the segregation study with other family members was performed using Sanger sequencing. This study identified a possible causative variant for ASD, c.2951G>A, in the FGD6 gene. We demonstrated the potential for ASD genetic variants associated with ASD using whole-exome sequencing and a bioinformatics filtering procedure. These techniques could be useful in identifying possible causative ASD variants, especially in cases in which variants cannot be identified by other techniques.