Beaulieu-Boycott-Innes syndrome (BBIS) is a rare autosomal recessive neurodevelopmental disorder with intellectual disability associated with mutations in THOC6. The clinical presentation includes moderate to severe intellectual disability, mild microcephaly, and non-life threatening congenital malformations including cardiac septal defects, structural renal anomalies, cryptorchidism in males, submucous cleft palate, and corpus callosum dysgenesis. THOC6 is a part of the THO complex, which is involved in coordinating mRNA processing with export.