Gain-of-function mutations in the phosphatidylserine synthase 1 (PTDSS1) gene cause Lenz-Majewski syndrome

Nat Genet. 2014 Jan;46(1):70-6. doi: 10.1038/ng.2829. Epub 2013 Nov 17.


Lenz-Majewski syndrome (LMS) is a syndrome of intellectual disability and multiple congenital anomalies that features generalized craniotubular hyperostosis. By using whole-exome sequencing and selecting variants consistent with the predicted dominant de novo etiology of LMS, we identified causative heterozygous missense mutations in PTDSS1, which encodes phosphatidylserine synthase 1 (PSS1). PSS1 is one of two enzymes involved in the production of phosphatidylserine. Phosphatidylserine synthesis was increased in intact fibroblasts from affected individuals, and end-product inhibition of PSS1 by phosphatidylserine was markedly reduced. Therefore, these mutations cause a gain-of-function effect associated with regulatory dysfunction of PSS1. We have identified LMS as the first human disease, to our knowledge, caused by disrupted phosphatidylserine metabolism. Our results point to an unexplored link between phosphatidylserine synthesis and bone metabolism.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Adolescent
  • Animals
  • Cells, Cultured
  • Child
  • Dwarfism
  • Embryo, Nonmammalian
  • Female
  • Fibroblasts / metabolism
  • Humans
  • Hyperostosis
  • Male
  • Molecular Sequence Data
  • Mutation*
  • Nitrogenous Group Transferases / genetics*
  • Nitrogenous Group Transferases / metabolism
  • Phosphatidylserines / biosynthesis
  • Phosphatidylserines / genetics
  • Syndrome
  • Zebrafish / embryology
  • Zebrafish / genetics


  • Phosphatidylserines
  • Nitrogenous Group Transferases
  • phospholipid serine base exchange enzyme

Associated data

  • RefSeq/NM_014754
  • RefSeq/NP_055569
  • SWISSPROT/P48651