rs745861849
Variant summary
Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PM2_Supporting
This summary comes from the ClinGen Evidence Repository: The NM_000152.5:c.725C>A variant in GAA is a missense variant predicted to cause substitution of Ala by Glu at amino acid 242 (p.Ala242Glu). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00028 (7/24910 alleles) in the African population, which is lower than the ClinGen Lysosomal Diseases VCEP’s threshold for PM2 (<0.001), meeting this criterion (PM2_Supporting). The computational predictor REVEL gives a score of 0.528 which is neither above nor below the thresholds predicting a damaging (>0.7) or benign (<0.5) impact on GAA function (neither PP3 nor BP4 is met). It has not been reported in the literature as causative for GAA-related disease, but has been observed in 9 asymptomatic newborn screening cases by a clinical testing laboratory cases. In those cases, the c.1630G>A (p.Val544Met) variant (ClinVar Variation ID; 450358), classified as a variant of uncertain significance by the ClinGen LD VCEP on June 6, 2024), was always present suggesting that the two variants are in cis. There is a ClinVar entry for this variant (Variation ID: 642648). In summary, this variant meets the criteria to be classified as Uncertain significance for Pompe disease based on the ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert panel (specifications Version 2.0): PM2_supporting.(Classification approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on May 21, 2024). LINK:https://erepo.genome.network/evrepo/ui/classification/CA8815003/MONDO:0009290/010
Frequency
Consequence
NM_000152.5 missense
Scores
Clinical Significance
Conservation
Publications
- glycogen storage disease IIInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), PanelApp Australia, ClinGen, G2P
- glycogen storage disease due to acid maltase deficiency, infantile onsetInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- glycogen storage disease due to acid maltase deficiency, late-onsetInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Uncertain_significance. The variant received 1 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000526 AC: 8AN: 152112Hom.: 0 Cov.: 34 show subpopulations
GnomAD2 exomes AF: 0.0000159 AC: 4AN: 251102 AF XY: 0.00 show subpopulations
GnomAD4 exome AF: 0.00000411 AC: 6AN: 1460914Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0AN XY: 726778 show subpopulations
GnomAD4 genome AF: 0.0000526 AC: 8AN: 152112Hom.: 0 Cov.: 34 AF XY: 0.0000404 AC XY: 3AN XY: 74302 show subpopulations
ClinVar
Submissions by phenotype
Glycogen storage disease, type II Uncertain:5
The NM_000152.5:c.725C>A variant in GAA is a missense variant predicted to cause substitution of Ala by Glu at amino acid 242 (p.Ala242Glu). The highest population minor allele frequency in gnomAD v2.1.1 is 0.00028 (7/24910 alleles) in the African population, which is lower than the ClinGen Lysosomal Diseases VCEP’s threshold for PM2 (<0.001), meeting this criterion (PM2_Supporting). The computational predictor REVEL gives a score of 0.528 which is neither above nor below the thresholds predicting a damaging (>0.7) or benign (<0.5) impact on GAA function (neither PP3 nor BP4 is met). It has not been reported in the literature as causative for GAA-related disease, but has been observed in 9 asymptomatic newborn screening cases by a clinical testing laboratory cases. In those cases, the c.1630G>A (p.Val544Met) variant (ClinVar Variation ID; 450358), classified as a variant of uncertain significance by the ClinGen LD VCEP on June 6, 2024), was always present suggesting that the two variants are in cis. There is a ClinVar entry for this variant (Variation ID: 642648). In summary, this variant meets the criteria to be classified as Uncertain significance for Pompe disease based on the ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert panel (specifications Version 2.0): PM2_supporting. (Classification approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on May 21, 2024). -
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This sequence change replaces alanine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 242 of the GAA protein (p.Ala242Glu). This variant is present in population databases (rs745861849, gnomAD 0.03%). This variant has not been reported in the literature in individuals affected with GAA-related conditions. ClinVar contains an entry for this variant (Variation ID: 642648). 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) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on GAA protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
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not provided Uncertain:2
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GAA-related disorder Uncertain:1
The GAA c.725C>A variant is predicted to result in the amino acid substitution p.Ala242Glu. To our knowledge, this variant has not been reported in the literature. Two variants affecting the same amino acid residue (c.725C>T Ala242Val and c.726G>A Ala242Ala) have been reported in individuals with glycogen storage disease 2 (c.725C>T Ala242Val reported in Kroos et al 2008. PubMed ID: 18425781; c.726G>A Ala242Ala reported in Gragnaniello et al 2022. PubMed ID: 36310651). This variant is reported in 0.028% of alleles in individuals of African descent in gnomAD (http://gnomad.broadinstitute.org/variant/17-78081388-C-A). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at