PNPLA1 and autosomal recessive congenital ichthyosis: Ten genes are currently known to be associated with ARCI: TGM1, ALOXE3, ALOX12B, NIPAL4, ABCA12, CYP4F22, PNPLA1, CERS3, SDR9C7, and SULT2B1. Mutations in TGM1 account for most ARCI cases.