Screening for Fragile X Syndrome Among Filipino Children with Autism Spectrum Disorder.

Researchers tested 235 Filipino children with autism (ages 2-6) to see if they also had Fragile X Syndrome, a genetic condition that can cause autism-like symptoms. They found no children with full Fragile X Syndrome, only one child who was a 'carrier' of the genetic change. This suggests Fragile X Syndrome may be less common in Filipino children with autism compared to other populations, but more research is needed to confirm this finding.

This cross-sectional study screened 235 Filipino children aged 2-6 years with confirmed autism spectrum disorder for Fragile X Syndrome (FXS) using PCR analysis of CGG repeats in the FMR1 gene. Results showed 93.6% had normal results, no full FXS mutations were detected, one child (0.436%) was identified as a premutation carrier, and 14 children (5.95%) had intermediate alleles. These findings suggest FXS prevalence may be lower in Filipino/Asian populations compared to non-Asian populations, consistent with previous research indicating 0-6.5% FXS rates in autism populations globally. The study contributes important preliminary data on genetic causes of autism in the Philippines.

Provides first data on FXS prevalence in Filipino children with autism, supporting potentially lower rates in Asian populations. Results may inform genetic screening protocols and counseling approaches for Filipino families, though larger representative studies needed to establish definitive prevalence rates and clinical guidelines.

Self-referred sample may not represent broader Filipino autism population, biased toward families with clinical access. Limited to high-risk autism group, cannot establish general population prevalence. Did not test for mosaicism, DNA methylation, or AGG patterns that could affect results.

Individuals with autism spectrum disorder present with difficulties in social communication, restricted interests or behaviors and other co-morbidities. About 2 to 10% of cases of autism have a genetic cause, and Fragile X Syndrome (FXS) is reported in 0 to 6.5% of individuals with autism. However, the FXS and premutation prevalence among Filipino children has never been reported. The aim of the study was to establish the presence of FXS or premutation carriers among Filipino children with autism and to describe the phenotypic characteristic of cases identified.

Blood was collected from 235 children aged 2-6 years old and diagnosed with autism. Samples were analyzed using PCR methods to amplify CGG repeats in the FMRI gene. The diagnosis of autism was confirmed through the Autism Diagnostic Observation Schedule-2. Additional characteristics were documented from a physical examination, Griffiths Scales of Child Development assessment and a parent-answered questionnaire using the Vineland Adaptive Behavior Scale.

Fragile X testing through PCR methods in 235 children with diagnosed autism showed 220 (93.6%) were negative, no full mutations, 1 (0.436%) premutation carrier and 14 (5.95%) cases contained intermediate alleles. The FXS testing was limited to confirmed cases of autism, which is considered a high-risk group and does not provide prevalence for the general Filipino population. Subjects were self-referred or referred by clinicians, which may not represent the Filipino autism population with a bias towards those with means for clinical consultations and ability to travel to the place of testing. Samples were not measured for mosaicism, DNA methylation or AGG interspersion patterns.

These may have effects on the CGG repeat expansion and overall presentation of FXS. Findings from a single premutation carrier cannot characterize features distinctly present in Filipinos with the mutation. Nevertheless, these results support the data that the prevalence of FXS in Asian populations may be lower than non-Asian populations. This can contribute to a better understanding of FXS and genetic causes of autism in the Philippines and other Asian populations.