chr5-71656808-C-T

Variant names:

• chr5-71656808-C-T
• rs778172446
• NM_022132.5:c.1640C>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_022132.5(MCCC2):​c.1640C>T​(p.Ala547Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000479 in 1,461,822 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A547T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: MCCC2 NM_022132.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 6.14
• Publications: 0 publications found

Genes affected

MCCC2 (HGNC:6937): (methylcrotonyl-CoA carboxylase subunit 2) This gene encodes the small 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. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, May 2018]

MCCC2 Gene-Disease associations (from GenCC):

• 3-methylcrotonyl-CoA carboxylase 2 deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• 3-methylcrotonyl-CoA carboxylase deficiency

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MCCC2	NM_022132.5	c.1640C>T	p.Ala547Val	missense_variant	Exon 17 of 17	ENST00000340941.11	NP_071415.1
MCCC2	NM_001363147.1	c.1526C>T	p.Ala509Val	missense_variant	Exon 16 of 16		NP_001350076.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MCCC2	ENST00000340941.11	c.1640C>T	p.Ala547Val	missense_variant	Exon 17 of 17	1	NM_022132.5	ENSP00000343657.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000119 AC: 3 AN: 251428 AF XY: 0.00000736

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461822 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727214

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.0000696 AC: 6 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.000173 AC: 1 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111966

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

3-methylcrotonyl-CoA carboxylase 2 deficiency Uncertain:2

Nov 27, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 547 of the MCCC2 protein (p.Ala547Val). This variant is present in population databases (rs778172446, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with MCCC2-related conditions. ClinVar contains an entry for this variant (Variation ID: 535827). 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 MCCC2 protein function. 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. -

Nov 11, 2019

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Pathogenic	0.28
CADD	Benign	21
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.89	D
Eigen	Uncertain	0.40
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.94	D
M_CAP	Uncertain	0.12	D
MetaRNN	Uncertain	0.57	D
MetaSVM	Pathogenic	0.90	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		6.1
PrimateAI	Uncertain	0.66	T
PROVEAN	Uncertain	-3.5	D
REVEL	Pathogenic	0.76
Sift	Uncertain	0.020	D
Sift4G	Benign	0.18	T
Polyphen		0.72	P
Vest4		0.43
MutPred		0.59		Gain of loop (P = 3e-04);
MVP		0.96
MPC		0.27
ClinPred		0.94	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.47
gMVP		0.87
Mutation Taster		=22/78	disease causing

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

Other links and lift over

dbSNP: rs778172446; hg19: chr5-70952635;