Hereditary Motor and Sensory Neuropathy with Agenesis of the Corpus Callosum (HMSN/ACC) [OMIM #218000] is an autosomal recessive condition characterized by severe progressive sensorimotor neuropathy resulting in hypotonia, areflexia and amyotrophy, variable degrees of dysgenesis of the corpus callosum and dymorphic
features. MRI shows complete callosal agenesis in 60% of individuals, partial callosal agenesis in 10%, and normal corpus callosum in 30%. Dysmorphic features can include hypertelorism, syndactyly and high-arched palates. Individuals are able to stand or walk with support at 4 – 6 years. Physical and intellectual ability
deteriorate over time and most affected individuals are severely impaired by adolescence.
Mutations of the SLC12A6 [OMIM #604878] gene have been identified in patients with HMSN/ACC.