J Korean Acad Child Adolesc Psychiatry.  2026 Jan;37(1):63-69. 10.5765/jkacap.250023.

Screening of CGG Trinucleotide Repeats Within FMR1 Gene in Bangladeshi Children With Autism Spectrum Disorder: Exploring a Possible Link With Fragile X Syndrome

• Noman AA
• Saba AA
• Adiba M
• Rahman M
• Sayem M
• Nabi AN
• Yasmin T

• KMID: 2576150
• DOI: http://doi.org/10.5765/jkacap.250023

Abstract

Objectives
Autism spectrum disorder (ASD) is a major neurodevelopmental disorder characterized by persistent deficits in social communication along with restricted, repetitive patterns of behaviour and interests. FMR1 gene, which causes Fragile X syndrome (FXS), is the most common single-gene contributor to ASD. Variations in CGG repeat length within the 5' untranslated region of FMR1 are central to the etiology of FXS. Given the established connection between FXS and ASD, this study investigated whether the trinucleotide repeat region of FMR1 is associated with ASD in Bangladeshi children.
Methods
Seventy-one children participated in the study, including 39 with ASD and 32 age-matched controls. The FMR1 region was amplified using polymerase chain reaction and subsequently sequenced.
Results
There was no statistically significant difference in the number of CGG repeats between patients with ASD and controls (p>0.01), with the most common repeat number being 27 in both groups. Interspersion of the two AGG trinucleotides among the CGG repeats was the most common pattern found in the study participants, with frequencies of 56.67% and 50.00% in the ASD and the control groups, respectively.
Conclusion
This study provides preliminary evidence that CGG repeat expansion in the FMR1 gene is unlikely to represent a major genetic contributor to ASD in Bangladeshi children. However, given the limited sample size, further investigations with a larger cohort are required to confirm these findings.

Keyword

Autism spectrum disorder; Fragile X syndrome; Trinucleotide repeat; Trinucleotide repeat expansion; Neurodevelopmental disorders