Functional assessment of TSC1 missense variants identified in individuals with tuberous sclerosis complex

Marianne Hoogeveen-Westerveld, Rosemary Ekong, Sue Povey, Izabela Karbassi, Sat Dev Batish, Johan T. den Dunnen, Agnies van Eeghen, Elizabeth Thiele, Karin Mayer, Kira Dies, Li Wen, Catherine Thompson, Steven P. Sparagana, Peter Davies, Cora Aalfs, Ans van den Ouweland, Dicky Halley, Mark Nellist

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Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutations in the TSC1 or TSC2 genes. The TSC1 and TSC2 gene products, TSC1 and TSC2, form a complex that inhibits the mammalian target of rapamycin (mTOR) complex 1 (TORC1). Previously, we demonstrated that pathogenic amino acid substitutions in the N-terminal domain of TSC1 (amino acids 50-224) are destabilizing. Here we investigate an additional 21 unclassified TSC1 variants. Our functional assessment identified four substitutions (p.L61R, p.G132D, p.F158S, and p.R204P) between amino acids 50 and 224 that reduced TSC1 stability and prevented the TSC1-TSC2-dependent inhibition of TORC1. In four cases (20%), our functional assessment did not agree with the predictions of the SIFT amino acid substitution analysis software. Our new data confirm our previous finding that the N-terminal region of TSC1 is essential for TSC1 function. © 2011 Wiley-Liss, Inc.
Original languageEnglish
Pages (from-to)476-479
JournalHuman mutation
Issue number3
Publication statusPublished - 2012

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