rs754460336
Variant summary
Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PP3_ModeratePP5_Very_Strong
The NM_020166.5(MCCC1):c.196C>T(p.Arg66Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000291 in 1,614,002 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R66H) has been classified as Uncertain significance.
Frequency
Consequence
NM_020166.5 missense
Scores
Clinical Significance
Conservation
Publications
- 3-methylcrotonyl-CoA carboxylase 1 deficiencyInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
- 3-methylcrotonyl-CoA carboxylase deficiencyInheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
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ACMG classification
Our verdict: Pathogenic. The variant received 10 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| MCCC1 | NM_020166.5 | c.196C>T | p.Arg66Cys | missense_variant | Exon 3 of 19 | ENST00000265594.9 | NP_064551.3 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000394 AC: 6AN: 152142Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000636 AC: 16AN: 251472 AF XY: 0.0000515 show subpopulations
GnomAD4 exome AF: 0.0000280 AC: 41AN: 1461860Hom.: 0 Cov.: 32 AF XY: 0.0000303 AC XY: 22AN XY: 727226 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000394 AC: 6AN: 152142Hom.: 0 Cov.: 32 AF XY: 0.0000673 AC XY: 5AN XY: 74320 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
3-methylcrotonyl-CoA carboxylase 1 deficiency Pathogenic:3
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This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 66 of the MCCC1 protein (p.Arg66Cys). This variant is present in population databases (rs754460336, gnomAD 0.02%). This missense change has been observed in individual(s) with MCCC1-related conditions (PMID: 36822454; Invitae). 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: 542949). 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) has been performed at Invitae 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 MCCC1 protein function. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
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Methylcrotonyl-CoA carboxylase deficiency Pathogenic:1
Variant summary: MCCC1 c.196C>T (p.Arg66Cys) results in a non-conservative amino acid change located in the Biotin carboxylase-like, N-terminal domain (IPR005481) 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 6.4e-05 in 251472 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in MCCC1 causing Methylcrotonyl-CoA Carboxylase Deficiency (6.4e-05 vs 0.0042), allowing no conclusion about variant significance. c.196C>T has been reported in the literature in individuals affected with Methylcrotonyl-CoA Carboxylase Deficiency (Men_2023, Cheng_2023). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. One submitter has provided a clinical-significance assessment for this variant to ClinVar after 2014 without evidence for independent evaluation, and classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at