rs777829351
Variant summary
Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP5
The NM_001182.5(ALDH7A1):āc.664A>Gā(p.Thr222Ala) variant causes a missense change. The variant allele was found at a frequency of 0.0000285 in 1,612,886 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_001182.5 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 3 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
ALDH7A1 | NM_001182.5 | c.664A>G | p.Thr222Ala | missense_variant | Exon 7 of 18 | ENST00000409134.8 | NP_001173.2 | |
ALDH7A1 | NM_001201377.2 | c.580A>G | p.Thr194Ala | missense_variant | Exon 7 of 18 | NP_001188306.1 | ||
ALDH7A1 | NM_001202404.2 | c.664A>G | p.Thr222Ala | missense_variant | Exon 7 of 16 | NP_001189333.2 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152160Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000200 AC: 5AN: 249894Hom.: 0 AF XY: 0.00000741 AC XY: 1AN XY: 135014
GnomAD4 exome AF: 0.0000288 AC: 42AN: 1460726Hom.: 0 Cov.: 30 AF XY: 0.0000220 AC XY: 16AN XY: 726576
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152160Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74346
ClinVar
Submissions by phenotype
Pyridoxine-dependent epilepsy Pathogenic:4Uncertain:1
This variant was classified as: Likely pathogenic. This variant was detected in homozygous state. -
Variant summary: ALDH7A1 c.664A>G (p.Thr222Ala) results in a non-conservative amino acid change located in the Aldehyde dehydrogenase domain (IPR015590) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 2e-05 in 249894 control chromosomes (gnomAD). c.664A>G has been reported in the literature as a biallelic genotype in multiple individuals affected with Pyridoxine-Dependent Epilepsy (e.g. Tumiene_2018, Coughlin_2019). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Five ClinVar submitters have assessed the variant since 2014: two classified the variant as uncertain significance, one as likely pathogenic, and two as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
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This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 222 of the ALDH7A1 protein (p.Thr222Ala). This variant is present in population databases (rs777829351, gnomAD 0.006%). This missense change has been observed in individual(s) with pyridoxine-dependent epilepsy (PMID: 29286531, 30043187; internal data). ClinVar contains an entry for this variant (Variation ID: 204833). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt ALDH7A1 protein function with a positive predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -
not provided Pathogenic:1
In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 32956737, 30043187, 29286531) -
Inborn genetic diseases Uncertain:1
The p.T222A variant (also known as c.664A>G), located in coding exon 7 of the ALDH7A1 gene, results from an A to G substitution at nucleotide position 664. The threonine at codon 222 is replaced by alanine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at