A Distinct Autism-like Phenotype in Bardet-Biedl Syndrome Case Report

Bardet-Biedl syndrome is an autosomal recessive ciliopathy characterized by a combination of physical findings, neurodevelopmental and behavioral components, including speech delay, learning difficulties, and autistic traits. Behavioral and neurodevelopmental symptoms are often overlooked, with either under-recognition of an autism-like phenotype or overdiagnosis of Autism Spectrum Disorder (ASD). A 10-year-old girl presented with speech delay, polydactyly, night blindness, truncal obesity, type 2 diabetes, seizure episode, borderline intelligence, and learning difficulties. She was diagnosed with bardet Biedl Syndrome (BBS) using the established major and minor criteria by Forsythe et al. She was specifically referred for poor social interaction and, in school, irritability and poor communication with peers. She was earlier diagnosed with ASD elsewhere. On further evaluation, she had selective mutism, stereotypical behaviors, such as arranging her books, and lacked pretend play. The Indian Scale for Assessment of Autism (ISAA) yielded a score of 71, consistent with mild ASD. Even though she had a score of mild ASD on ISAA, clinically, she did not fit into the ASD criteria according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM 5) guidelines. She had autistic traits: Selective mutism and stereotypical behavior restricted to bookshelf arrangement. This case highlights overdiagnosis of ASD in the presence of autistic traits, whereas she appears to have a distinct behavioral phenotype associated with BBS, not fulfilling DSM 5 criteria for ASD.