17-42565668-C-T
Variant summary
Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2PP3_StrongPP5_Very_Strong
The NM_025233.7(COASY):c.1495C>T(p.Arg499Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000248 in 1,614,010 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★).
Frequency
Consequence
NM_025233.7 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 14 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152214Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.0000239 AC: 6AN: 251206Hom.: 0 AF XY: 0.0000147 AC XY: 2AN XY: 135786
GnomAD4 exome AF: 0.0000260 AC: 38AN: 1461796Hom.: 0 Cov.: 33 AF XY: 0.0000316 AC XY: 23AN XY: 727208
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152214Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0AN XY: 74364
ClinVar
Submissions by phenotype
Neurodegeneration with brain iron accumulation 6 Pathogenic:5
This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 499 of the COASY protein (p.Arg499Cys). This variant is present in population databases (rs140709867, gnomAD 0.009%). This missense change has been observed in individual(s) with neurodegeneration with brain iron accumulation (PMID: 24360804, 27021474, 28489334). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 100662). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt COASY protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects COASY function (PMID: 24360804). For these reasons, this variant has been classified as Pathogenic. -
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PS3 PM3 PM2 PM1 -
This sequence change is predicted to replace arginine with cysteine at codon 499 of the COASY protein (p.(Arg499Cys)). The arginine residue is evolutionarily conserved (100 vertebrates, UCSC), and is a critical residue for ATP binding and phosphotransfer reaction in the dephospho-CoA kinase (DPCK) domain (PMID: 21264299). There is a large physicochemical difference between arginine and cysteine. The variant is present in a large population cohort at a frequency of 0.002% (rs140709867, 6/251,206 alleles, 0 homozygotes in gnomAD v2.1), which is consistent with recessive disease. The variant has been identified in the homozygous state and compound heterozygous with a second pathogenic allele in at least four individuals with neurodegeneration with brain iron accumulation (NBIA) and segregates with disease (PMID: 24360804, 28489334; DECIPHER; Royal Melbourne Hospital). The variant disrupts enzyme activity in functional assays and a yeast model partially recapitulates the NBIA phenotype (PMID: 24360804, 28357284). Additionally, reduced COASY expression and de novo CoA biosynthesis has been demonstrated in patient fibroblasts (PMID: 24360804). Multiple lines of computational evidence predict a deleterious effect for the missense substitution (5/6 algorithms). Based on the classification scheme RMH Modified ACMG Guidelines v1.3.1, this variant is classified as PATHOGENIC. Following criteria are met: PM3_Strong, PM1, PS3_Supporting, PM2_Supporting, PP1, PP3, PP4. -
This variant was determined to be pathogenic according to ACMG Guidelines, 2015 [PMID:25741868]. This variant has been previously reported as pathogenic [PMID 24360804, 28489334, 28688840] -
Neurodegeneration with brain iron accumulation Pathogenic:1
Variant summary: COASY c.1495C>T (p.Arg499Cys) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2.4e-05 in 251206 control chromosomes. c.1495C>T has been reported in the literature in multiple individuals affected with Neurodegeneration With Brain Iron Accumulation (example Dusi_2014, Evers_2017 and Hiraide_2021 etc.) These data indicate that the variant is very likely to be associated with disease. At least two publications report experimental evidence reporting significant decrease in enzyme function and decrease in protein accumulation (example Dusi_2014 and Berti_2015 etc). Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
not provided Pathogenic:1
Published functional studies demonstrate a damaging effect showing a loss of enzyme activity (Dusi et al., 2014); Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 28688840, 27021474, 28489334, 24360804, 29531224, 25870938, 27141409, 28357284, 27892483) -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at