MBOAT7 -Associated Intellectual Developmental Disorder-57 with Global Developmental Delay: A Whole Exome Sequencing Case Report

Intellectual developmental disorder-57 (MRT57) is a rare autosomal recessive neurodevelopmental disorder caused by biallelic pathogenic variants in the MBOAT7 gene. The disorder is characterized by global developmental delay, intellectual disability, severe speech impairment, behavioral abnormalities, and variable motor dysfunction. Due to overlapping clinical manifestations, affected patients are commonly misdiagnosed with cerebral palsy or nonspecific developmental delay before genetic confirmation. We report a 7-year-old male child who presented with delayed speech and language development and delayed developmental milestones. Due to persistent developmental concerns and the presence of a similarly affected sibling, a hereditary neurodevelopmental disorder was suspected. Whole exome sequencing (WES) found a homozygous frameshift variant in the MBOAT7 gene, c.168del (p. Ile57Serfs*52). The same variant was detected in the affected sibling, supporting autosomal recessive inheritance. This case shows the importance of considering genetic causes in children presenting with delayed speech, language impairment, and developmental delay. Molecular diagnosis through WES enabled definitive diagnosis, appropriate genetic counseling, and informed clinical management.