ALDH3A2 and ichthyosis: Sjögren‐Larsson syndrome (SLS) is an autosomal recessive leukodystrophy characterized by ichthyosis, intellectual disability, and progressive spastic paralysis caused by biallelic pathogenic variants in the ALDH3A2 gene that encodes the fatty aldehyde dehydrogenase, fatty aldehyde dehydrogenase (FALDH); FALDH catalyzes several metabolic reactions involved in fatty aldehyde oxidation.