ClinVar Miner

Submissions for variant NM_002234.4(KCNA5):c.544G>A (p.Gly182Arg) (rs755408841)

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Total submissions: 2
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Submitter RCV SCV Clinical significance Condition Last evaluated Review status Method Comment
Invitae RCV001087399 SCV000646994 likely benign Atrial fibrillation, familial, 7 2020-10-30 criteria provided, single submitter clinical testing
Stanford Center for Inherited Cardiovascular Disease, Stanford University RCV000786331 SCV000925106 uncertain significance not provided 2018-01-24 no assertion criteria provided provider interpretation p.Gly182Arg (G182R; c.544G>A) in exon 1 of the KCNA5 gene (NM_002234.3; ENST00000252321.4) Chromosome position: 12:5153857 G / A Found in a male patient with early-onset lone atrial fibrillation. The KCNA5 gene has been associated with familial atrial fibrillation. Based on the information reviewed below, including its relatively high frequency among individuals with Latino ancestry like our patient, we classify it as a Variant of Uncertain Significance, Probably Benign, concluding that there is not sufficient evidence for its pathogenicity to warrant using it for predictive genetic testing. This variant has previously been reported in two individuals with idiopathic pulmonary hypertension both taking part in the same study (Remillard et al. 2007; PMID: 17267549), and one with Brugada syndrome (Proost et al. 2017). There is no informative segregation information. Of note, 12% of the participants in the Remillard study were Hispanic. The researchers reported that this missense change affects KCNA5 channel inactivation and localization in vitro (Burg et al. 2010; PMID: 20018952), although it does form functional channels. According to these authors, the variant is located in the highly conserved NH2-terminal tetramerization domain (T1) of KV channels which is important for proper channel assembly, association with regulatory subunits, and localization of the channel to the plasma membrane. They note that the glycine at position 182 is 100% identical in the T1 domains of all 17 human KCNA (KV1), KV2 (KCNB), KV3 (KCNC), and KV4 (KCND) subunits examined (KCNA1–7, KCNA10, KCNB1–2, KCNC1–4, and KCND1–3). This is a distinctly nonconservative amino acid change, resulting in the replacement of a nonpolar Glycine with a positively-charge Arginine with a much larger side-chain. Glycine at this location is absolutely conserved across ~100 vertebrate species for which we have data. The adjacent residues are also very highly conserved. There are no Likely Pathogenic or Pathogenic variants currently listed in ClinVar within 10 amino acids to either side. This variant was reported in 54 individuals in the gnomAD database, which includes variant calls on ~140,000 individuals of European, African, Latino, South Asian, Ashkenazi, and East Asian descent. Specifically, the variant was observed in 41 Latinos (for the highest allele frequency: 0.12%), 3 East Asians, 8 non-Finnish Europeans, 1 African, and 1 “Other” ancestry individual. It is present at a higher frequency than would be expected for a pathogenic variant, and is particularly prevalent among individuals with our patient’s Latino ancestry—which suggests that it might be a benign ethnicity-specific variant. The phenotype of the individuals in gnomAD is not publicly available. The dataset is comprised of multiple cohorts, some of which were recruited from the general population, others were enriched for common cardiovascular disease. The curators made an effort to exclude individuals with severe pediatric diseases.

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