First Reported Co-Occurrence of Bardet-Biedl Syndrome Type 10 and Autism Spectrum Disorder: A Case Report and Clinical Review.

Abstract

Introduction: Bardet-Biedl syndrome (BBS) is a genetically heterogeneous, multisystemic ciliopathy, whereas autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social interaction and restricted, repetitive behaviors. While both conditions are independently associated with genetic etiologies, their co-occurrence is exceptionally rare. To date, no prior report has confirmed such co-occurrence through molecular genetic analysis.

Case presentation: We report a 4-year-old male diagnosed with both BBS type 10 and ASD. Whole exome sequencing (WES) revealed a homozygous pathogenic variant in the BBS10 gene and a novel heterozygous intronic variant in the OGT gene, classified as a variant of uncertain significance. Clinically, the patient exhibited features consistent with both disorders, including retinal degeneration, polydactyly, renal anomalies, hypotonia, and ASD-specific behavioral patterns.

Conclusion: This case represents the first genetically confirmed co-occurrence of BBS10 and ASD. The identification of a potentially contributory non-coding variant in the OGT gene provides novel insight into the shared genetic and pathophysiological mechanisms underlying ciliopathies and neurodevelopmental disorders. The findings emphasize the importance of dual diagnostic consideration in complex pediatric cases and demonstrate the value of genomic analysis in revealing rare genetic overlaps.