NM_000255.4:c.278G>A
Variant summary
Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM2PP3_ModeratePP5_Very_Strong
The NM_000255.4(MMUT):c.278G>A(p.Arg93His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000335 in 1,614,118 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_000255.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 12 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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MMUT | NM_000255.4 | c.278G>A | p.Arg93His | missense_variant | Exon 2 of 13 | ENST00000274813.4 | NP_000246.2 | |
MMUT | XM_005249143.4 | c.278G>A | p.Arg93His | missense_variant | Exon 2 of 13 | XP_005249200.1 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000460 AC: 7AN: 152122Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000636 AC: 16AN: 251462Hom.: 0 AF XY: 0.0000589 AC XY: 8AN XY: 135906
GnomAD4 exome AF: 0.0000322 AC: 47AN: 1461878Hom.: 0 Cov.: 31 AF XY: 0.0000234 AC XY: 17AN XY: 727246
GnomAD4 genome AF: 0.0000460 AC: 7AN: 152240Hom.: 0 Cov.: 32 AF XY: 0.0000672 AC XY: 5AN XY: 74428
ClinVar
Submissions by phenotype
Methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency Pathogenic:6Other:1
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Based on the classification scheme VCGS_Germline_v1.3.5, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with methylmalonic aciduria, mut(0) type (MIM#251000). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to histidine. (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD (v4) <0.01 for a recessive condition (54 heterozygotes, 0 homozygotes). (SP) 0309 - Multiple alternative amino acid changes at the same position have been observed in gnomAD (v4) (highest allele count: 86 heterozygotes, 0 homozygotes). (I) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in the annotated methylmalonyl-CoA mutase domain (DECIPHER). (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been reported as pathogenic by multiple clinical laboratories in ClinVar, and has also been reported as compound heterozygous and homozygous in individuals with methylmalonic acidaemia in the literature (PMIDs: 26615597, 38455531). (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
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not provided Pathogenic:3
This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 93 of the MUT protein (p.Arg93His). This variant is present in population databases (rs121918251, gnomAD 0.04%). This missense change has been observed in individuals with methylmalonic aciduria (PMID: 1670635, 16281286, 16490061). ClinVar contains an entry for this variant (Variation ID: 1880). 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 MUT protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects MUT function (PMID: 1670635, 7912889, 16281286). For these reasons, this variant has been classified as Pathogenic. -
Published functional studies demonstrate a damaging effect on propionate incorporation and protein function (Raff ML et al, 1991; Crane et al., 1994); 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: 33413471, 33726816, 1670635, 31523617, 31622506, 16281286, 7912889, 16490061) -
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MMUT-related disorder Pathogenic:1
The MMUT c.278G>A variant is predicted to result in the amino acid substitution p.Arg93His. This variant has been reported in the compound heterozygous or homozygous state in many unrelated individuals with methylmalonic aciduria (Raff et al. 1991. PubMed ID: 1670635; Worgan et al. 2006. PubMed ID: 16281286; Kang et al. 2019. PubMed ID: 31622506). Functional assays on patient fibroblasts indicate this variant reduces enzyme activity (Worgan et al. 2006. PubMed ID: 16281286). This variant is reported in 0.048% of alleles in individuals of European (Finnish) descent in gnomAD. In summary, this variant is interpreted as pathogenic. -
Methylmalonic acidemia Pathogenic:1
Variant summary: MUT c.278G>A (p.Arg93His) results in a non-conservative amino acid change located in the Methylmalonyl-CoA mutase catalytic alpha chain of 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 6.1e-05 in 277218 control chromosomes (gnomAD). This frequency is not significantly higher than expected for a pathogenic variant in MUT causing Methylmalonic Acidemia (6.1e-05 vs 0.0024), allowing no conclusion about variant significance. The variant, c.278G>A, has been reported in the literature in multiple homozygous individuals affected with Methylmalonic Acidemia (Imtiaz_2014). These data indicate that the variant is very likely to be associated with disease. The variant was reported in skin fibroblasts derived from a patient with neonatal methylmalonic aciduria, with no detectable methylmalonyl CoA mutase apoenzyme activity (Raff_1991). One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
METHYLMALONIC ACIDURIA, mut(0) TYPE Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at