3-183017300-T-C

Variant names:

• chr3-183017300-T-C
• rs992786696
• NM_020166.5:c.2015A>G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_020166.5(MCCC1):​c.2015A>G​(p.Asp672Gly) variant causes a missense change. The variant allele was found at a frequency of 0.00000434 in 1,613,832 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 Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: MCCC1 NM_020166.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.13

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]

MCCC1-AS1 (HGNC:40366): (MCCC1 antisense RNA 1)

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.885

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MCCC1	NM_020166.5	c.2015A>G	p.Asp672Gly	missense_variant	Exon 18 of 19	ENST00000265594.9	NP_064551.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MCCC1	ENST00000265594.9	c.2015A>G	p.Asp672Gly	missense_variant	Exon 18 of 19	1	NM_020166.5	ENSP00000265594.4

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152200 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000965

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461632 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2 AN XY: 727144

Gnomad4 AFR exome AF: 0.0000896

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152200 Hom.: 0 Cov.: 33 AF XY: 0.0000404 AC XY: 3 AN XY: 74342

Gnomad4 AFR AF: 0.0000965

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: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Aug 02, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.2015A>G (p.D672G) alteration is located in exon 18 (coding exon 18) of the MCCC1 gene. This alteration results from a A to G substitution at nucleotide position 2015, causing the aspartic acid (D) at amino acid position 672 to be replaced by a glycine (G). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

3-methylcrotonyl-CoA carboxylase 1 deficiency Uncertain:1

Sep 17, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces aspartic acid with glycine at codon 672 of the MCCC1 protein (p.Asp672Gly). The aspartic acid residue is moderately conserved and there is a moderate physicochemical difference between aspartic acid and glycine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with MCCC1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.72	D;T;T
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Benign	0.079	D
MetaRNN	Pathogenic	0.89	D;D;D
MetaSVM	Uncertain	0.020	D
MutationAssessor	Pathogenic	2.9	M;.;.
PrimateAI	Benign	0.42	T
PROVEAN	Pathogenic	-4.8	D;D;.
REVEL	Uncertain	0.62
Sift	Uncertain	0.013	D;D;.
Sift4G	Uncertain	0.023	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.91
MVP		0.85
MPC		0.70
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.58
gMVP		0.82

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs992786696; hg19: chr3-182735088;