Screening for Fragile X Syndrome Among Filipino Children with Autism Spectrum Disorder.
Fragile X full mutations seem almost absent in Filipino children with autism, but intermediate gene changes occur in about six percent.
01Research in Context
What this study did
Doctors tested 235 Filipino children who already had an autism diagnosis. They looked for gene changes linked to fragile X syndrome.
They checked for three types of gene repeats: full mutation, premutation, and intermediate alleles.
What they found
No child had the full fragile X mutation. One child had a premutation and 14 had intermediate alleles.
That means about six in every 100 Filipino kids with autism carry a fragile X gene change, but not the full syndrome.
How this fits with other research
Tabatadze et al. (2025) tested 441 Georgian children with autism or ID. They found the full mutation in one of every 17 kids.
The two studies look opposite: 0% versus 5.9% full mutation. The gap is likely ethnic. Different groups carry fragile X at different rates.
Tassone et al. (2013) ran a similar screen in the U.S. and also found positive cases. Together, these papers show that checking for fragile X in autism is worth doing, but the yield depends on the child's background.
Why it matters
If you work with Filipino clients, full fragile X is probably rare, yet one in 16 still has a related gene change. A quick genetic referral can clarify risk and guide family planning. Add fragile X to your intake checklist, but keep expectations realistic: a negative result is far more likely than a positive one.
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02At a glance
03Original abstract
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.
Journal of autism and developmental disorders, 2023 · doi:10.1038/gim.2012.34