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

• Main Authors: Sérgio B. Sousa, Dagan Jenkins, Estelle Chanudet, Guergana Tasseva, Miho Ishida, Glenn Anderson, James Docker, Mina Ryten, Joaquim Sa, Jorge M. Saraiva, Angela Barnicoat, Richard Scott, Alistair Calder, Duangrurdee Wattanasirichaigoon, Krystyna Chrzanowska, Martina Simandlová, Lionel Van Maldergem, Philip Stanier, Philip L. Beales, Jean E. Vance, Gudrun E. Moore
• Other Authors: UCL Institute of Child Health
• Format: Article
• Published: 2018
• Subjects: Biochemistry, Genetics and Molecular Biology
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/33503
• Institution: Mahidol University

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. © 2014 Nature America, Inc.