5-71587486-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_022132.5(MCCC2):c.61C>T(p.Arg21Cys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: MCCC2 NM_022132.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.86

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.787

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MCCC2	NM_022132.5	c.61C>T	p.Arg21Cys	missense_variant	1/17	ENST00000340941.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MCCC2	ENST00000340941.11	c.61C>T	p.Arg21Cys	missense_variant	1/17	1	NM_022132.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1385010 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 683500

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 23, 2023

The c.61C>T (p.R21C) alteration is located in exon 1 (coding exon 1) of the MCCC2 gene. This alteration results from a C to T substitution at nucleotide position 61, causing the arginine (R) at amino acid position 21 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.36
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
Cadd	Pathogenic	27
Dann	Pathogenic	1.0
DEOGEN2	Benign	0.022	T;T;.
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.89	D;D;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.79	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.77	T
Sift4G	Uncertain	0.0020	D;D;D
Polyphen		1.0	.;D;D
Vest4		0.51
MutPred		0.44		Gain of catalytic residue at P20 (P = 0.0073);Gain of catalytic residue at P20 (P = 0.0073);Gain of catalytic residue at P20 (P = 0.0073);
MVP		0.98
MPC		0.42
ClinPred		0.96	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Varity_R		0.24
gMVP		0.69

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: rs1744805925; hg19: chr5-70883313;