LAUSR

BACKGROUND Agenesis of the corpus callosum (ACC) is a relatively common brain malformation in children with developmental disabilities, caused by mutations in many genes. These genetic causes are characterized by their extreme heterogeneity with more than 300 causative genes identified to date. CASE REPORT We describe two new cases from a three-generation family with ACC and a de novo mutation of the sonic hedgehog (SHH) gene. The affected family members had mild intellectual disability, broad forehead, and widely spaced eyes. A next-generation sequencing (NGS) approach revealed a stop-gain mutation (NM_000193.2:c.1300_1301insA p.Trp434Ter) of the SHH gene; it is the first family to report ACC associated with a single SHH gene mutation. CONCLUSION ACC with mild intellectual disability and facial dysmorphism may be caused by a mutation in SHH, but further research investigating the genotype-phenotype correlation of SHH mutations is required.