A de novo LoF variant in the KMT2C gene was identified in an ASD proband from the Simon Simplex Collection (PMIDs 22495309), while a second de novo LoF variant in this gene was identified in one ASD proband from 2,270 trios screened by the Autism Sequencing Consortium (PMID 25363760). Analysis of rare coding variation in 3,871 ASD cases and 9,937 ancestry-matched or paternal controls from the Autism Sequencing Consortium (ASC) identified KMT2C as a gene meeting high statistical significance with a 0.01 < FDR 0.05, meaning that this gene had a 95% chance of being a true autism gene (PMID 25363760). Additional de novo probably damaging missense variants in KMT2C were identified in ASD probands from the Simons Simplex Collection (Iossifov et al., 2014; Krumm et al., 2015). A de novo LoF variant in KMT2C was identifed in a proband from the Pediatric Cardiac Genetics Consortium who presented with ASD, developmental delay, and intellectual disability in addition to congenital heart disease (Homsy et al., 2015). Koemans et al., 2017 identified four patients with intellectual disability, language delay, and motor delay that carried de novo LoF variants in the KMT2C gene; two of these patients presented with autism, one patient presented with PDD-NOS, and one presented with autistic traits. Three de novo variants (two protein-truncating variants, one missense variant) were identified in ASD probands from the Autism Sequencing Consortium in Satterstrom et al., 2020; subsequent TADA analysis of de novo variants from the Simons Simplex Collection and the Autism Sequencing Consortium and protein-truncating variants from iPSYCH in this report identified KMT2C as a candidate gene with a false discovery rate (FDR) 0.01. Additional de novo loss-of-function variants and potentially damaging missense variants in the KMT2C gene were reported in ASD probands from the SPARK cohort in Zhou et al., 2022; a two-stage analysis of rare de novo and inherited coding variants in 42,607 ASD cases, including 35,130 new cases from the SPARK cohort, in this report identified KMT2C as a gene reaching exome-wide significance (P < 2.5E-06).
Molecular Function
Histone methyltransferase that methylates 'Lys-4' of histone H3; H3 'Lys-4' methylation represents a specific tag for epigenetic transcriptional activation. Central component of the MLL2/3 complex, a coactivator complex of nuclear receptors, involved in transcriptional coactivation. KMT2C/MLL3 may be a catalytic subunit of this complex.
External Links
References
Type
Title
Type of Disorder
Associated Disorders
Author, Year
Primary
Sporadic autism exomes reveal a highly interconnected protein network of de novo mutations.
Trr is required in the mushroom body for short term memory. Trr binds in the promoter of genes involved in neuronal processes. Pan-neuronal trr knockdown in fly heads leads to gene misregulation, including the Drosophila ortholog of Arc (Arc1).
References
Type
Title
Author, Year
Primary
Functional convergence of histone methyltransferases EHMT1 and KMT2C involved in intellectual disability and autism spectrum disorder.
Model Type:
Genetic
Model Genotype:
Wild type
Mutation:
Since homozygous mutations in trr are lethal, the authors used the UAS/Gal4 system and inducible RNA interference (RNAi) to assess the role of trr in the adult fly nervous system. Knockdown of trr was targeted specifically to the mushroom body using R14H06-Gal4. To estimate the knockdown efficiency the authors co-expressed UAS-trr-RNAi with UAS-mCD8::GFP and performed immunohistochemistry using a trr antibody.
Allele Type: Knockdown
Strain of Origin: Not specified
Genetic Background: Not specified
ES Cell Line: Not specified
Mutant ES Cell Line: Not specified
Model Source: Janelia FlyLight collection
Description: Flies expressing the trr-RNAi construct did not exhibit a significant reduction in courting index in response to rejection compared to controls, indicating a loss of short-term memory.
Exp Paradigm: Wildtype male flies exhibit a learned reduction of courtship behaviour after rejection by a non-receptive premated female.
Description: Mutants show decreased levels of trr in the mushroom body compared to controls.
Exp Paradigm: Cells expressing trr RNAi are marked by UAS-mCD8::GFP.