CTNNB1 and spastic diplegia: Since the first discovery of loss-of-function mutations in intellectual disability patients (1), CTNNB1 has been established as a causative gene of neurodevelopmental disorder with spastic diplegia and visual defects (NEDSDV), which is characterized by global developmental delay, intellectual disability, facial dysmorphism, and microcephaly (MIM# 615075) (2).