5-71649189-A-G
Variant summary
Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1PM2PP5
The NM_022132.5(MCCC2):c.1309A>G(p.Ile437Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000421 in 1,614,094 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_022132.5 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 5 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
MCCC2 | NM_022132.5 | c.1309A>G | p.Ile437Val | missense_variant | Exon 14 of 17 | ENST00000340941.11 | NP_071415.1 | |
MCCC2 | NM_001363147.1 | c.1195A>G | p.Ile399Val | missense_variant | Exon 13 of 16 | NP_001350076.1 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000328 AC: 5AN: 152226Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000199 AC: 5AN: 251480Hom.: 0 AF XY: 0.0000147 AC XY: 2AN XY: 135914
GnomAD4 exome AF: 0.0000431 AC: 63AN: 1461868Hom.: 0 Cov.: 32 AF XY: 0.0000399 AC XY: 29AN XY: 727234
GnomAD4 genome AF: 0.0000328 AC: 5AN: 152226Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74374
ClinVar
Submissions by phenotype
3-methylcrotonyl-CoA carboxylase 2 deficiency Pathogenic:3Uncertain:2
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This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 437 of the MCCC2 protein (p.Ile437Val). RNA analysis indicates that this missense change induces altered splicing and may result in an absent or altered protein product. This variant is present in population databases (rs119103224, gnomAD 0.005%). This missense change has been observed in individual(s) with 3 methylcrotonyl-CoA carboxylase deficiency (PMID: 22642865; internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 1925). 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 not expected to disrupt MCCC2 protein function with a negative predictive value of 80%. Studies have shown that this missense change results in activation of a cryptic donor site, and produces a non-functional protein and/or introduces a premature termination codon (PMID: 11181649). For these reasons, this variant has been classified as Pathogenic. -
The MCCC2 c.1309A>G (p.Ile437Val) variant is described in two studies in which it is found in a compound heterozygous state in one individual and in a heterozygous state in another individual, both with 3-methylcrotonyl-CoA carboxylase (3-MCC) deficiency (Baumgartner et al. 2001; Grünert et al. 2012). The p.Ile437Val variant was not present in 100 controls (Grünert et al. 2012) and is reported at a frequency of 0.00005 in the European (non-Finnish) population of the Genome Aggregation Database. Functional studies using RT-PCR showed that the p.Ile437Val variant activates a cryptic splice donor site, which when used results in the deletion of the last 64 base pairs of exon 14 from the mature transcript. Direct sequencing of the RT-PCR product showed that virtually all the transcript present uses the new donor site (Baumgartner et al. 2001). Based on the evidence, the p.Ile437Val variant is classified as a variant of unknown significance but suspicious for pathogenicity for 3-MCC deficiency. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -
not provided Pathogenic:2
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at