Mendeliome
Gene: KCNQ1OT1 Amber List (moderate evidence)I don't know
Limited evidence that isolated intragenic variation in KCNQ1OT1 is definitively associated with a phenotype.
KCNQ1OT1 encodes the regulatory antisense non-coding RNA KCNQ1OT1 (KCNQ1 overlapping) and is located within the KCNQ1OT1:TSS DMR (imprinting control region 2; IC2) at 11p15.5. IC2 is located within KCNQ1 intron 10. KCNQ1OT1 is maternally imprinted and paternally expressed. On the paternal chromosome, KCNQ1OT1 is transcribed and represses in cis the flanking imprinted genes, including the growth inhibitor CDKN1C, which is normally transcribed from the maternal allele. In 50% of the BWS patients, loss of methylation (LOM) of IC2 leads to biallelic expression of KCNQ1OT1 and biallelic silencing of CDKN1C (PMID 30635621). Expression is increased in BWS due to IC2 epimutations or paternal UPD.
Single nucleotide variants within KCNQ1OT1 have not been definitively associated with human disease. A heterozygous maternally inherited non-coding variant was identified in an individual with isolated omphalocele. This variant was shown to alter the methylation pattern of the imprinted allele (PMID 29047350).
Eggerman et al (PMID 32447323) described a 132 base pair deletion within KCNQ1OT1 associated with growth retardation in the case of paternal but not maternal transmission. This intragenic deletion did not affect IC2 methylation.
Microdeletions of IC2 involving KCNQ1OT1 on the paternal allele have been identified in a small number of patients with Russell-Silver syndrome. Similarly, microdeletions of IC2 involving KCNQ1OT1 on the maternal allele have been identified in a small number of patients with BWS. These deletions also variably involve KCNQ1 or CDKN1C. LoF in CDKN1C is a known cause of BWS. There is some evidence to suggest that disruption of KCNQ1 prevents maternal methylation at IC2 (PMID 30778172).
Sources: Expert ReviewCreated: 17 Oct 2021, 6:12 a.m.
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, maternally imprinted (paternal allele expressed)
Phenotypes
Beckwith-Wiedemann syndrome OMIM:130650; Russell-Silver Syndrome
Publications
Gene: kcnq1ot1 has been classified as Amber List (Moderate Evidence).
Gene: kcnq1ot1 has been classified as Red List (Low Evidence).
gene: KCNQ1OT1 was added gene: KCNQ1OT1 was added to Mendeliome. Sources: Expert Review Mode of inheritance for gene: KCNQ1OT1 was set to MONOALLELIC, autosomal or pseudoautosomal, maternally imprinted (paternal allele expressed) Publications for gene: KCNQ1OT1 were set to 22205991; 15372379; 23511928; 30794780; 29377879; 10220444; 32447323; 33177595; 29047350 Phenotypes for gene: KCNQ1OT1 were set to Beckwith-Wiedemann syndrome OMIM:130650; Russell-Silver Syndrome Review for gene: KCNQ1OT1 was set to AMBER
If promoting or demoting a gene, please provide comments to justify a decision to move it.
Genes included in a Genomics England gene panel for a rare disease category (green list) should fit the criteria A-E outlined below.
These guidelines were developed as a combination of the ClinGen DEFINITIVE evidence for a causal role of the gene in the disease(a), and the Developmental Disorder Genotype-Phenotype (DDG2P) CONFIRMED DD Gene evidence level(b) (please see the original references provided below for full details). These help provide a guideline for expert reviewers when assessing whether a gene should be on the green or the red list of a panel.
A. There are plausible disease-causing mutations(i) within, affecting or encompassing an interpretable functional region(ii) of this gene identified in multiple (>3) unrelated cases/families with the phenotype(iii).
OR
B. There are plausible disease-causing mutations(i) within, affecting or encompassing cis-regulatory elements convincingly affecting the expression of a single gene identified in multiple (>3) unrelated cases/families with the phenotype(iii).
OR
C. As definitions A or B but in 2 or 3 unrelated cases/families with the phenotype, with the addition of convincing bioinformatic or functional evidence of causation e.g. known inborn error of metabolism with mutation in orthologous gene which is known to have the relevant deficient enzymatic activity in other species; existence of an animal model which recapitulates the human phenotype.
AND
D. Evidence indicates that disease-causing mutations follow a Mendelian pattern of causation appropriate for reporting in a diagnostic setting(iv).
AND
E. No convincing evidence exists or has emerged that contradicts the role of the gene in the specified phenotype.
(i)Plausible disease-causing mutations: Recurrent de novo mutations convincingly affecting gene function. Rare, fully-penetrant mutations - relevant genotype never, or very rarely, seen in controls. (ii) Interpretable functional region: ORF in protein coding genes miRNA stem or loop. (iii) Phenotype: the rare disease category, as described in the eligibility statement. (iv) Intermediate penetrance genes should not be included.
It’s assumed that loss-of-function variants in this gene can cause the disease/phenotype unless an exception to this rule is known. We would like to collect information regarding exceptions. An example exception is the PCSK9 gene, where loss-of-function variants are not relevant for a hypercholesterolemia phenotype as they are associated with increased LDL-cholesterol uptake via LDLR (PMID: 25911073).
If a curated set of known-pathogenic variants is available for this gene-phenotype, please contact us at panelapp@genomicsengland.co.uk
We classify loss-of-function variants as those with the following Sequence Ontology (SO) terms:
Term descriptions can be found on the PanelApp homepage and Ensembl.
If you are submitting this evaluation on behalf of a clinical laboratory please indicate whether you report variants in this gene as part of your current diagnostic practice by checking the box
Standardised terms were used to represent the gene-disease mode of inheritance, and were mapped to commonly used terms from the different sources. Below each of the terms is described, along with the equivalent commonly-used terms.
A variant on one allele of this gene can cause the disease, and imprinting has not been implicated.
A variant on the paternally-inherited allele of this gene can cause the disease, if the alternate allele is imprinted (function muted).
A variant on the maternally-inherited allele of this gene can cause the disease, if the alternate allele is imprinted (function muted).
A variant on one allele of this gene can cause the disease. This is the default used for autosomal dominant mode of inheritance where no knowledge of the imprinting status of the gene required to cause the disease is known. Mapped to the following commonly used terms from different sources: autosomal dominant, dominant, AD, DOMINANT.
A variant on both alleles of this gene is required to cause the disease. Mapped to the following commonly used terms from different sources: autosomal recessive, recessive, AR, RECESSIVE.
The disease can be caused by a variant on one or both alleles of this gene. Mapped to the following commonly used terms from different sources: autosomal recessive or autosomal dominant, recessive or dominant, AR/AD, AD/AR, DOMINANT/RECESSIVE, RECESSIVE/DOMINANT.
A variant on one allele of this gene can cause the disease, however a variant on both alleles of this gene can result in a more severe form of the disease/phenotype.
A variant in this gene can cause the disease in males as they have one X-chromosome allele, whereas a variant on both X-chromosome alleles is required to cause the disease in females. Mapped to the following commonly used term from different sources: X-linked recessive.
A variant in this gene can cause the disease in males as they have one X-chromosome allele. A variant on one allele of this gene may also cause the disease in females, though the disease/phenotype may be less severe and may have a later-onset than is seen in males. X-linked inactivation and mosaicism in different tissues complicate whether a female presents with the disease, and can change over their lifetime. This term is the default setting used for X-linked genes, where it is not known definitately whether females require a variant on each allele of this gene in order to be affected. Mapped to the following commonly used terms from different sources: X-linked dominant, x-linked, X-LINKED, X-linked.
The gene is in the mitochondrial genome and variants within this can cause this disease, maternally inherited. Mapped to the following commonly used term from different sources: Mitochondrial.
Mapped to the following commonly used terms from different sources: Unknown, NA, information not provided.
For example, if the mode of inheritance is digenic, please indicate this in the comments and which other gene is involved.