The PSAT1 gene encodes an enzyme that is involved in the synthesis of the L-serine amino acid. The phosphoserine aminotransferase enzyme catalyzes the second step in the 3-step serine biosynthesis pathway, the conversion of 3-phosphohydroxypyruvate into 3-phosphoserine. As an amino acid, serine is required for protein synthesis. It is also a precursor to compounds such as sphingomyelin and cysteine and neuromodulators such as glycine. Hence, any defects in the serine biosynthesis pathway can have strong pathological consequences.
Mutations in PSAT1 result in Neu-Laxova syndrome 2 (NLS2), a severe fatal disorder characterized by ichthyosis, microcephaly, intra-uterine growth retardation, nervous system abnormalities, limb deformities, edema, and facial dysmorphia. The gene is also associated with Phosphoserine Aminotransferase Deficiency (PSATD), a less severe phenotype characterized by congenital microcephaly, hypertonia, psychomotor retardation, and seizures.