6-49440273-C-T
Variant summary
Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong
The NM_000255.4(MMUT):c.1889G>A(p.Gly630Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000366 in 1,613,946 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/20 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G630A) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000255.4 missense
Scores
Clinical Significance
Conservation
Publications
- methylmalonic aciduria due to methylmalonyl-CoA mutase deficiencyInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P
- vitamin B12-unresponsive methylmalonic acidemia type mut-Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- vitamin B12-unresponsive methylmalonic acidemia type mut0Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 19 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| MMUT | NM_000255.4 | c.1889G>A | p.Gly630Glu | missense_variant | Exon 11 of 13 | ENST00000274813.4 | NP_000246.2 | |
| MMUT | XM_005249143.4 | c.1889G>A | p.Gly630Glu | missense_variant | Exon 11 of 13 | XP_005249200.1 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152156Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000119 AC: 3AN: 251332 AF XY: 0.0000221 show subpopulations
GnomAD4 exome AF: 0.0000376 AC: 55AN: 1461790Hom.: 0 Cov.: 32 AF XY: 0.0000248 AC XY: 18AN XY: 727204 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152156Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3AN XY: 74322 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Pathogenic:2
The G630E missense likely pathogenic variant in the MUT gene has been reported previously in association with methylmalonic acidemia (MMA) (Crane, A. and Ledley, F., 1994). The G630E variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species and in silico analysis predicts this variant is probably damaging to the protein structure/function. A missense variant in a nearby residue (V633G) has been reported in the Human Gene Mutation Database in association with MMA (Stenson et al., 2014), supporting the functional importance of this region of the protein. Therefore, this variant is likely pathogenic; however, the possibility that it is benign cannot be excluded -
This sequence change replaces glycine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 630 of the MUT protein (p.Gly630Glu). This variant is present in population databases (rs143023066, gnomAD 0.002%). This missense change has been observed in individual(s) with methylmalonic acidemia (PMID: 7912889, 17113806, 24865477, 27167370, 28811685). ClinVar contains an entry for this variant (Variation ID: 426995). 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: 7912889). For these reasons, this variant has been classified as Pathogenic. -
Methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency Pathogenic:2
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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. -
Methylmalonic acidemia Pathogenic:1
Variant summary: MUT c.1889G>A (p.Gly630Glu) results in a non-conservative amino acid change located in the Cobalamin (vitamin B12)-binding domain (IPR006158) 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 1.2e-05 in 251524 control chromosomes (gnomAD and publication data). c.1889G>A has been reported in the literature in individuals affected with Methylmalonic Acidemia, including at least one homozygote (Crane_1994, Worgan_2006, Forny_2016, Kang_2019). These data indicate that the variant is likely to be associated with disease. At least one functional study reports experimental evidence evaluating an impact on protein function and this variant effect results in reducing enzymatic activity (Crane_1994). Three ClinVar submitters (evaluation after 2014) cite the variant as pathogenic (n=1) and likely pathogenic (n=2). Based on the evidence outlined above, the variant was classified as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at