DNA methylation episignature for Witteveen-Kolk syndrome due to SIN3A haploinsufficiency

Genet Med. 2023 Jan;25(1):63-75. doi: 10.1016/j.gim.2022.10.004. Epub 2022 Nov 18.

Abstract

Purpose: Witteveen-Kolk syndrome (WITKOS) is a rare, autosomal dominant neurodevelopmental disorder caused by heterozygous loss-of-function alterations in the SIN3A gene. WITKOS has variable expressivity that commonly overlaps with other neurodevelopmental disorders. In this study, we characterized a distinct DNA methylation epigenetic signature (episignature) distinguishing WITKOS from unaffected individuals as well as individuals with other neurodevelopmental disorders with episignatures and described 9 previously unpublished individuals with SIN3A haploinsufficiency.

Methods: We studied the phenotypic characteristics and the genome-wide DNA methylation in the peripheral blood samples of 20 individuals with heterozygous alterations in SIN3A. A total of 14 samples were used for the identification of the episignature and building of a predictive diagnostic biomarker, whereas the diagnostic model was used to investigate the methylation pattern of the remaining 6 samples.

Results: A predominantly hypomethylated DNA methylation profile specific to WITKOS was identified, and the classifier model was able to diagnose a previously unresolved test case. The episignature was sensitive enough to detect individuals with varying degrees of phenotypic severity carrying SIN3A haploinsufficient variants.

Conclusion: We identified a novel, robust episignature in WITKOS due to SIN3A haploinsufficiency. This episignature has the potential to aid identification and diagnosis of individuals with WITKOS.

Keywords: DNA methylation; Epigenetics; SIN3A; WITKOS; Witteveen-Kolk syndrome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA Methylation* / genetics
  • Genome
  • Haploinsufficiency / genetics
  • Humans
  • Neurodevelopmental Disorders* / genetics