New SMS missense mutation leads to a striking reduction in spermine synthase protein function and a severe form of Snyder-Robinson XLMR syndrome

ArticleinJournal of Medical Genetics 45(8):539-43 · July 2008with17 Reads
Impact Factor: 6.34 · DOI: 10.1136/jmg.2007.056713 · Source: PubMed


    We report the identification of a novel mutation at a highly conserved residue within the N-terminal region of spermine synthase (SMS) in a second family with Snyder-Robinson X-linked mental retardation syndrome (OMIM 309583). This missense mutation, p.G56S, greatly reduces SMS activity and leads to severe epilepsy and cognitive impairment. Our findings contribute to a better delineation and expansion of the clinical spectrum of Snyder-Robinson syndrome, support the important role of the N-terminus in the function of the SMS protein, and provide further evidence for the importance of SMS activity in the development of intellectual processing and other aspects of human development.