Methylation Pattern and Repeat Expansion Screening in a Cohort of Boys with Autism Spectrum Disorders: Correlation of Genetic Findings with Clinical Presentations.

Researchers tested 226 boys with autism in Romania to look for Fragile X syndrome, which is the most common single genetic cause of autism. They found 4 boys (1.8%) had the genetic changes that cause Fragile X syndrome. Three of these boys showed typical signs of the condition. The study showed that even with the same genetic condition, children can have very different symptoms - from mild to severe learning difficulties and different behavioral challenges.

This study screened 226 Romanian boys with autism spectrum disorders for genetic and epigenetic defects in the FMR1 gene, which causes Fragile X syndrome (FXS) - the most common single-gene cause of autism. Using methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) and triplet-primed PCR methods, researchers identified FMR1 full mutations in 4 patients (1.8%), consistent with rates from larger international studies. Three of the four boys showed typical clinical features correlating with their genetic findings. The study demonstrated significant clinical variability among children with FXS, ranging from mild to severe intellectual disability, atypical to characteristic physical features, and various behavioral presentations.

The combined testing approach proved effective for comprehensively identifying genetic defects responsible for Fragile X syndrome.

The 1.8% yield supports routine FMR1 screening in boys with ASD. Combined MS-MLPA and TP-PCR testing approaches provide comprehensive genetic assessment. Clinical variability in FXS patients emphasizes need for individualized assessment and intervention planning, even when genetic diagnosis is established.

Small sample size of identified FXS cases (n=4) limits analysis of clinical variability. Single population study from Romania may not be generalizable to other populations. Limited clinical characterization details provided in the abstract.

Autism spectrum disorders (ASDs) are neurodevelopmental conditions with early onset of clinical manifestations. ASD etiology is highly heterogeneous, with genetic factors being strong determinants of the behavioral problems and neurodevelopmental deficits. Fragile X syndrome (FXS) (OMIM #300624), caused by the transcriptional silencing of thegene, represents the most common monogenic cause of autism. Our study included 226 boys with a diagnosis of ASD, for a systematic screening of genetic and epigenetic defects in thegene promoter in a Romanian pediatric cohort.

The methods, methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) and triplet-primed PCR (TP-PCR)/melt curve analysis (MCA), were chosen for their ability to detect the methylation anomalies (the former) as well as repeat expansions in thepromoter (the latter). Both methods used in our screening generated concordant results, detectingfull mutation in 4 out of 226 patients (~1.8%). This yield is similar to data obtained in larger studies. Three out of four boys presented the typical clinical features, in correlation with genetic findings.

The combined use of MS-MLPA and TP-PCR/MCA-based assay was, in our experience, useful to fully describe the genetic defects responsible for FXS. A significant variability of clinical presentations was observed in our small group of children with FXS, from mild to severe intellectual disability and from atypical to characteristic dysmorphic features, as well as various behavioral problems.