DNA methylation signature inNSD2loss-of-function variants appeared similar to that in Wolf-Hirschhorn syndrome

Abstract

AbstractPurposeWolf-Hirschhorn syndrome (WHS), a contiguous gene syndrome caused by the hemizygous deletion of the distal short arm of chromosome 4 whereNSD2is, reportedly exhibits specific DNA methylation signatures in peripheral blood cells. However, responsible genomic loci for signatures are unreported. The objective of the study is to define the loci of WHS-related DNA methylation signatures and to explore the role ofNSD2for the signatures.MethodsWe conducted genome-wide methylation analysis of individuals with WHS orNSD2variants using array. We studied genome-edited knock in mice or induced pluripotent stem cells to explore the function ofNSD2variants which are observed in congenital anomaly cases.ResultsThree undiagnosed cases withNSD2variants showed WHS-related DNA methylation signatures. These variants were validated to beNSD2loss-of-function in induced pluripotent stem cells or genome-edited knock-in mice. p.Pro905Leu variant decreased Nsd2 protein levels, and changed Histone H3-Lysine 36 demethylation levels in similar way in the same genomic regions asNsd2knock out mice regulated.Nsd2knock out mice exhibited common DNA methylation changes.ConclusionThese results revealed that WHS-related DNA methylation signatures are dependent onNSD2dysfunction and are useful in diagnosingNSD2variants of unknown significance.