rs796051985

Variant names:

• chr3-183041639-CCA-C
• rs796051985
• NM_020166.5:c.1193_1194delTG

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_020166.5(MCCC1):​c.1193_1194delTG​(p.Val398GlyfsTer19) variant causes a frameshift change. The variant allele was found at a frequency of 0.00000805 in 1,614,066 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: MCCC1 NM_020166.5 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 3.78

Genes affected

MCCC1 (HGNC:6936): (methylcrotonyl-CoA carboxylase subunit 1) This gene encodes the large subunit of 3-methylcrotonyl-CoA carboxylase. This enzyme functions as a heterodimer and catalyzes the carboxylation of 3-methylcrotonyl-CoA to form 3-methylglutaconyl-CoA. Mutations in this gene are associated with 3-Methylcrotonylglycinuria, an autosomal recessive disorder of leucine catabolism. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-183041639-CCA-C is Pathogenic according to our data. Variant chr3-183041639-CCA-C is described in ClinVar as [Pathogenic]. Clinvar id is 203798.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr3-183041639-CCA-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MCCC1	NM_020166.5	c.1193_1194delTG	p.Val398GlyfsTer19	frameshift_variant	Exon 11 of 19	ENST00000265594.9	NP_064551.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MCCC1	ENST00000265594.9	c.1193_1194delTG	p.Val398GlyfsTer19	frameshift_variant	Exon 11 of 19	1	NM_020166.5	ENSP00000265594.4

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152192 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251438 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135890

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000684 AC: 10 AN: 1461874 Hom.: 0 AF XY: 0.0000110 AC XY: 8 AN XY: 727238

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000899

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152192 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74356

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000113

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

3-methylcrotonyl-CoA carboxylase 1 deficiency Pathogenic:3

Feb 17, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 203798). This premature translational stop signal has been observed in individual(s) with 3-methylcrotonyl-CoA carboxylase deficiency (PMID: 22642865). This variant is present in population databases (rs796051985, gnomAD 0.002%). This sequence change creates a premature translational stop signal (p.Val398Glyfs*19) in the MCCC1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MCCC1 are known to be pathogenic (PMID: 11181649, 15359379, 22642865). -

Jun 12, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 18, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:2

Jun 12, 2014

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1193_1194delTG mutation in the MCCC1 gene has been reported previously in association with 3-methylcrotonyl-CoA carboxylase (3-MCC) deficiency (Grunert et al., 2012). The deletion causes a frameshift starting with codon Valine 398, changes this amino acid to a Glycine residue and creates a premature Stop codon at position 19 of the new reading frame, denoted p.Val398GlyfsX19. This mutation is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. Large deletions of one or more exons of the MCCC1 gene have been reported in association with 3-MCC deficiency (Eminoglu, FT et al., 2009; Wang et al., 2012). However, at this time the data is not sufficient to estimate the frequency of such mutations in MCCC1. In two separate studies of patients with a biochemically and/or enzymatically confirmed diagnosis of 3-MCC deficiency, two mutations were identified in either the MCCC1 or MCCC2 gene in 28/28 individuals (Stadler et al., 2006; Dantas et al., 2005). In another study, mutation analysis of both genes in 83 patients identified two mutations in 76 individuals; a single mutation was identified in the remaining patients (Grunert et al., 2012). The variant is found in MCCC1 panel(s). -

Jul 01, 2019

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs796051985; hg19: chr3-182759427;