CTDP1 and neuropathy: Congenital Cataracts, Facial Dysmorphism, and Neuropathy (CCFDN) Syndrome is a rare autosomal recessive disorder caused by the deep intronic variant c.863+389C>T (or IVS6+389C>T) in the Carboxy-Terminal Domain phosphatase subunit 1 (CTDP1) gene.