Expanding the Genotypic and Phenotypic Spectrum of Vissers-Bodmer Syndrome.

Vissers-Bodmer Syndrome (VIBOS) is a rare autosomal dominant neurodevelopmental disorder caused by variants in the CNOT1 gene. Affected individuals present with a broad clinical spectrum of developmental delays, intellectual disability, seizures, hypotonia, and behavioral challenges. Most affected individuals also have nonspecific dysmorphic facial features but no recognizable gestalt. We report a de novo pathogenic CNOT1 variant in a 6-month-old male patient who was evaluated for imperforate anus, partial agenesis of the corpus callosum, macrocephaly, hydronephrosis, overlapping toes, and fifth nail hypoplasia. Clinical trio exome sequencing identified a de novo heterozygous CNOT1 nonsense variant (c.4918C>T, p.(Arg1640*)) that has not been previously reported. The patient is now 3 years old and has no growth or developmental concerns in clinical follow-up. This case highlights a novel pathogenic CNOT1 variant and extends the clinical spectrum of VIBOS to include age-appropriate growth and neurodevelopment and the previously unreported presentation of imperforate anus. Recognition of these additional findings may facilitate earlier diagnosis and enhance understanding of the phenotypic variability associated with VIBOS.