5-71587493-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PM5 PP5_Moderate

The NM_022132.5(MCCC2):c.68A>G(p.Tyr23Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000144 in 1,385,764 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. Y23S) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MCCC2 NM_022132.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.07

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr5-71587493-A-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 2150106.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=1}.
• PP5: Variant 5-71587493-A-G is Pathogenic according to our data. Variant chr5-71587493-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2711697.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MCCC2	NM_022132.5	c.68A>G	p.Tyr23Cys	missense_variant	1/17	ENST00000340941.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MCCC2	ENST00000340941.11	c.68A>G	p.Tyr23Cys	missense_variant	1/17	1	NM_022132.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000749 AC: 1 AN: 133596 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 73064

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000408

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000144 AC: 2 AN: 1385764 Hom.: 0 Cov.: 32 AF XY: 0.00000146 AC XY: 1 AN XY: 683912

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000280

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: 9.27e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.0000113

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

3-methylcrotonyl-CoA carboxylase 2 deficiency Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jan 29, 2024

This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 23 of the MCCC2 protein (p.Tyr23Cys). This variant is present in population databases (no rsID available, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with MCCC2-related conditions. 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 with a positive predictive value of 95%. This variant disrupts the p.Tyr23 amino acid residue in MCCC2. Other variant(s) that disrupt this residue have been determined to be pathogenic (Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.36
Cadd	Pathogenic	27
Dann	Uncertain	1.0
DEOGEN2	Benign	0.034	T;T;.
Eigen	Uncertain	0.47
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.86	D;D;D
M_CAP	Pathogenic	0.73	D
MetaRNN	Uncertain	0.74	D;D;D
MetaSVM	Pathogenic	0.99	D
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.77	T
Sift4G	Uncertain	0.043	D;T;D
Polyphen		0.99, 0.98	.;D;D
Vest4		0.46
MutPred		0.32		Gain of loop (P = 0.0166);Gain of loop (P = 0.0166);Gain of loop (P = 0.0166);
MVP		0.95
MPC		0.44
ClinPred		0.94	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2
Varity_R		0.34
gMVP		0.71

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: rs1238687077; hg19: chr5-70883320;