rs544956641
Variant summary
Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1PM5PP2PP3_StrongPP5_Very_Strong
The NM_000187.4(HGD):c.365C>T(p.Ala122Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000248 in 1,613,906 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A122D) has been classified as Pathogenic.
Frequency
Consequence
NM_000187.4 missense
Scores
Clinical Significance
Conservation
Publications
- alkaptonuriaInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 17 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| HGD | NM_000187.4 | c.365C>T | p.Ala122Val | missense_variant | Exon 6 of 14 | ENST00000283871.10 | NP_000178.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| HGD | ENST00000283871.10 | c.365C>T | p.Ala122Val | missense_variant | Exon 6 of 14 | 1 | NM_000187.4 | ENSP00000283871.5 | ||
| HGD | ENST00000476082.2 | c.242C>T | p.Ala81Val | missense_variant | Exon 5 of 7 | 5 | ENSP00000419560.2 | |||
| HGD | ENST00000485313.5 | n.473C>T | non_coding_transcript_exon_variant | Exon 7 of 7 | 5 | |||||
| HGD | ENST00000492108.5 | n.-5C>T | upstream_gene_variant | 2 | ENSP00000419838.1 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152198Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000557 AC: 14AN: 251388 AF XY: 0.0000442 show subpopulations
GnomAD4 exome AF: 0.0000267 AC: 39AN: 1461590Hom.: 0 Cov.: 31 AF XY: 0.0000344 AC XY: 25AN XY: 727128 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152316Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74482 show subpopulations
ClinVar
Submissions by phenotype
Alkaptonuria Pathogenic:7
This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 122 of the HGD protein (p.Ala122Val). This variant is present in population databases (rs544956641, gnomAD 0.04%). This missense change has been observed in individual(s) with alkaptonuria (PMID: 12501223, 19862842, 23430897, 25804398). ClinVar contains an entry for this variant (Variation ID: 188865). 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 not expected to disrupt HGD protein function with a negative predictive value of 80%. For these reasons, this variant has been classified as Pathogenic.
A Homozygote Missense variant c.365C>T in Exon 6 of the HGD gene that results in the amino acid substitution p.Ala122Val was identified. The observed variant has a maximum allele frequency of 0.00006/--% in gnomAD exomes and genomes, respectively. The severity of the impact of this variant on the protein is medium, based on the effect of the protein and REVEL score . Rare Exome Variant Ensemble Learner (REVEL) is an ensembl method for predicting the pathogenicity of missense variants based on a combination of scores from 13 individual tools: MutPred, FATHMM v2.3, VEST 3.0, PolyPhen-2, SIFT, PROVEAN, MutationAssessor, MutationTaster, LRT, GERP++, SiPhy, phyloP, and phastCons. The REVEL score for an individual missense variant can range from 0 to 1, with higher scores reflecting greater likelihood that the variant is disease-causing. This variant has been reported as Pathogenic/Likely Pathogenic in the ClinVar database (Variant ID: 418295). This variant was reported among the patients for Alkaptonuria (Vilboux et al., 2009). Based on the above evidence this variant has been classified as Pathogenic according to the ACMG guidelines.
Experimental evidence suggests that this variant has 58% residual activity compared to the wild type indicating moderately tolerable variant (Lequeue S, et al., 2022). This variant shows a founder effect in Jordanian patients and is located in a mutational hot spot (Nemethova M, et al., 2016).
The variant was originally described in AKU patient in PMID:12501223. It has been submitted to the HGD gene mutation database (http://hgddatabase.cvtisr.sk/, DB-ID: AKU_00031).
This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at