AUTS2 Gene Variant Causing Intellectual Developmental Disorder, Autosomal Dominant 26 (MRD26): A Report of a Paediatric Case From the Arabian Peninsula

AUTS2-related intellectual developmental disorder type 26 is a rare neurodevelopmental condition characterised by variable clinical manifestations, including developmental delay, dysmorphic features, and behavioural abnormalities, which may contribute to delayed diagnosis. We report the case of a two and a half years old boy born to consanguineous parents who presented with global developmental delay, poor weight gain, feeding difficulties, recurrent choking episodes, and multiple dysmorphic features. Physical examination demonstrated arched eyebrows, broad nasal bridge, upturned philtrum, strabismus, mild lower limb hypotonia, unilateral cryptorchidism, and hypospadias. Delayed motor and speech milestones with autistic features were also observed. The patient additionally had recurrent upper respiratory tract infections and adenotonsillar hypertrophy requiring adenotonsillectomy. Given the multisystem involvement and developmental concerns, a genetic disorder was suspected. Whole-exome sequencing identified a heterozygous pathogenic variant in the AUTS2 gene, confirming the diagnosis of intellectual developmental disorder, autosomal dominant 26 (MRD26). To our knowledge, this represents the first reported case of MRD26 from the Arabian Peninsula and the Gulf Cooperation Council region. This case highlights the importance of maintaining a high index of suspicion in children presenting with developmental delay and dysmorphic features. It also contributes to the AUTS2 syndrome phenotypic database by adding a patient from a previously under-represented ethnic and geographical background, by documenting an autosomal dominant variant identified within a consanguineous pedigree, and by drawing attention to a constellation of co-occurring hypospadias, unilateral cryptorchidism, and adenotonsillar hypertrophy requiring surgery, which appears infrequently reported in the existing AUTS2 literature. Early diagnosis may facilitate timely multidisciplinary management, appropriate developmental support, and family counselling.