Faculty, Staff and Student Publications

Language

English

Publication Date

8-16-2025

Journal

Human Molecular Genetics

DOI

10.1093/hmg/ddaf082

PMID

40420380

PMCID

PMC12361114

PubMedCentral® Posted Date

5-27-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Rare variants affecting the epigenetic regulator KDM2B cause a recently delineated neurodevelopmental disorder. Interestingly, we previously identified both a general KDM2B-associated episignature and a subsignature specific to variants in the DNA-binding CxxC domain. In light of the existence of a distinct subsignature, we set out to determine if KDM2B CxxC variants are associated with a unique phenotype and disease mechanism. We recruited individuals with heterozygous CxxC variants and assessed the variants' effect on protein expression and DNA-binding ability. We analyzed clinical data from 19 individuals, including ten previously undescribed individuals with seven novel CxxC variants. The core phenotype of the KDM2B-CxxC cohort is more extensive as compared to that of individuals with KDM2B haploinsufficiency. All individuals with CxxC variants presented with developmental delay, mainly in the speech and motor domain, in addition to variable intellectual disability and mild facial dysmorphism. Congenital heart defects were observed in up to 78% of individuals, with additional common findings including musculoskeletal, ophthalmological, and urogenital anomalies, as well as behavioral challenges and feeding difficulties. Functional assays revealed that while mutant KDM2B protein with CxxC variants can be expressed in vitro, its DNA-binding ability is significantly reduced compared to wildtype. This study shows that KDM2B CxxC variants cause a distinct neurodevelopmental syndrome, possibly through a molecular mechanism different from haploinsufficiency.

Keywords

Humans, Jumonji Domain-Containing Histone Demethylases, Female, Male, Neurodevelopmental Disorders, Child, F-Box Proteins, Child, Preschool, Adolescent, Haploinsufficiency, Phenotype, Adult, Mutation, DNA-Binding Proteins, DNA, Protein Domains, Infant, Intellectual Disability, Developmental Disabilities, intellectual disability, congenital heart disease, chromatinopathy, clinical genetics, developmental delay

Published Open-Access

yes

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