Reduction of stratum corneum ceramides in Neu-Laxova syndrome caused by phosphoglycerate dehydrogenase deficiency

Neu-Laxova syndrome (NLS) is a very rare autosomal recessive congenital disorder characterized by disturbed development of the central nervous system and the skin and caused by mutations in any of the three genes involved in de novo l-serine biosynthesis: PHGDH, PSAT1, and PSPH. l-Serine is essential for the biosynthesis of phosphatidylserine and sphingolipids. The extracellular lipid of the stratum corneum, of which sphingolipid constitutes a significant part, plays a primary role in skin barrier function. Here, we describe a Japanese NLS pedigree with a previously unreported nonsense mutation in PHGDH and a unique inversion of chromosome 1. In addition, the levels of 11 major ceramide classes in the tape-stripped stratum corneum of the NLS patient's skin were assessed by LC/MS. Notably, lower amounts of ceramides of all classes were found in the patient's stratum corneum than in those of controls. This is the first report to demonstrate the reduction of ceramides in the stratum corneum of an NLS patient due to PHGDH mutations. The clinical findings and a detailed analysis of ceramides from the stratum corneum in the family extend the spectrum of clinical anomalies and give us a clue to the pathomechanisms of ichthyosis in NLS patients with phosphoglycerate dehydrogenase deficiency.