Heterozygous Variants in KMT2E Cause a Spectrum of Neurodevelopmental Disorders and Epilepsy.
Document Type
Article
Publication Date
6-6-2019
Identifier
DOI: 10.1016/j.ajhg.2019.03.021; PMCID: PMC6556837
Abstract
We delineate a KMT2E-related neurodevelopmental disorder on the basis of 38 individuals in 36 families. This study includes 31 distinct heterozygous variants in KMT2E (28 ascertained from Matchmaker Exchange and three previously reported), and four individuals with chromosome 7q22.2-22.23 microdeletions encompassing KMT2E (one previously reported). Almost all variants occurred de novo, and most were truncating. Most affected individuals with protein-truncating variants presented with mild intellectual disability. One-quarter of individuals met criteria for autism. Additional common features include macrocephaly, hypotonia, functional gastrointestinal abnormalities, and a subtle facial gestalt. Epilepsy was present in about one-fifth of individuals with truncating variants and was responsive to treatment with anti-epileptic medications in almost all. More than 70% of the individuals were male, and expressivity was variable by sex; epilepsy was more common in females and autism more common in males. The four individuals with microdeletions encompassing KMT2E generally presented similarly to those with truncating variants, but the degree of developmental delay was greater. The group of four individuals with missense variants in KMT2E presented with the most severe developmental delays. Epilepsy was present in all individuals with missense variants, often manifesting as treatment-resistant infantile epileptic encephalopathy. Microcephaly was also common in this group. Haploinsufficiency versus gain-of-function or dominant-negative effects specific to these missense variants in KMT2E might explain this divergence in phenotype, but requires independent validation. Disruptive variants in KMT2E are an under-recognized cause of neurodevelopmental abnormalities.
Journal Title
American journal of human genetics
Volume
104
Issue
6
First Page
1210
Last Page
1222
MeSH Keywords
Adolescent; Adult; Child; Child, Preschool; DNA-Binding Proteins; Epilepsy; Female; Genetic Variation; Haploinsufficiency; Heterozygote; Humans; Infant; Male; Neurodevelopmental Disorders; Pedigree; Phenotype; Young Adult
Keywords
H3K4 methylation; KMT2E; autism; epilepsy; epileptic encephalopathy; global developmental delay; intellectual disability; neurodevelopmental disorder
Recommended Citation
O'Donnell-Luria AH, Pais LS, Faundes V, et al. Heterozygous Variants in KMT2E Cause a Spectrum of Neurodevelopmental Disorders and Epilepsy. Am J Hum Genet. 2019;104(6):1210-1222. doi:10.1016/j.ajhg.2019.03.021
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Comments
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