Rare LRP6 Variants Identified in Spina Bifida Patients. Issue 3 (13th March 2015)

• Record Type: Journal Article
• Authors: Lei, Yunping; Fathe, Kristin; McCartney, Danielle; Zhu, Huiping; Yang, Wei; Ross, M. Elizabeth; Shaw, Gary M.; Finnell, Richard H.
• Is Part Of: Human mutation. Volume 36:Issue 3(2015:Mar.)
• Page Start: 342
• Page End: 349
• Publication Date: 2015-03-13
• Subjects: LRP6 -- SNV -- spina bifida -- Wnt signaling -- PCP signaling; Human chromosome abnormalities -- Periodicals; Mutation (Biology) -- Periodicals; 616.04205
• DOI: 10.1002/humu.22750
• Languages: English
• ISSNs: 1059-7794

Abstract

Abstract : This study identified four rare LRP6 single neucleotide variants in spina bifida cases. One variant, named p.Tyr544Cys, like Crooked tail and Ringleschwanz mouse variants, disrupted Lrp6 interaction with MESDC2 and impaired Lrp6 subcellular localization. Functional studies of the four LRP6 variants indicated that Lrp6 modulation of Wnt/PCP singaling might be more essential than its canonical Wnt pathway role in neural tube closure. ABSTRACT: Several single‐nucleotide variants (SNVs) in low‐density lipoprotein receptor‐related protein 6 ( Lrp6 ) cause neural tube defects (NTDs) in mice. We therefore examined LRP6 in 192 unrelated infants from California with the NTD, spina bifida, and found four heterozygous missense SNVs, three of which were predicted to be deleterious, among NTD cases and not in 190 ethnically matched nonmalformed controls. Parents and siblings could not be tested because of the study design. Like Crooked tail and Ringleschwanz mouse variants, the p.Tyr544Cys Lrp6 protein failed to bind the chaperone protein mesoderm development and impaired Lrp6 subcellular localization to the plasma membrane of MDCK II cells. Only the p.Tyr544Cys Lrp6 variant downregulated canonical Wnt signaling in a TopFlash luciferase reporter in vitro assay. In contrast, three Lrp6 mutants (p.Ala3Val, p.Tyr544Cys, and p.Arg1574Leu) increased noncanonical Wnt/planar cell polarity (PCP) signaling in an Ap1‐luciferase assay. Thus, LRP6 variants outside of YWTD repeats could potentially predispose embryos to NTDs, whereas Lrp6 modulation of Wnt/PCP signaling would be more essential than its canonical pathway role in neural tube closure.