ABHD5 and ichthyosis: ABHD5-syndromic epidermal differentiation disorder (ABHD5-sEDD; also known as Chanarin-Dorfman syndrome) is a rare autosomal recessive disorder caused by mutations in the α/β-hydrolase domain-containing 5 (ABHD5) gene, leading to systemic accumulation of neutral lipids and ichthyosis due to impaired activation of patatin-like phospholipase domain-containing (PNPLAs) proteins.