chr5-71650145-A-C

Variant names:

• chr5-71650145-A-C
• rs1554138549
• NM_022132.5:c.1450A>C

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Moderate PP5_Moderate

The NM_022132.5(MCCC2):​c.1450A>C​(p.Thr484Pro) variant causes a missense change involving the alteration of a conserved nucleotide. 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T484M) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MCCC2 NM_022132.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.32
• 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: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 9 uncertain in NM_022132.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.844
• PP5: Variant 5-71650145-A-C is Pathogenic according to our data. Variant chr5-71650145-A-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 467804.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MCCC2	NM_022132.5	c.1450A>C	p.Thr484Pro	missense_variant	Exon 15 of 17	ENST00000340941.11	NP_071415.1
MCCC2	NM_001363147.1	c.1336A>C	p.Thr446Pro	missense_variant	Exon 14 of 16		NP_001350076.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MCCC2	ENST00000340941.11	c.1450A>C	p.Thr484Pro	missense_variant	Exon 15 of 17	1	NM_022132.5	ENSP00000343657.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

3-methylcrotonyl-CoA carboxylase 2 deficiency Pathogenic:1

Jul 05, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (gnomAD no frequency). This sequence change replaces threonine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 484 of the MCCC2 protein (p.Thr484Pro). This missense change has been observed in individual(s) with 3-methylcrotonyl-CoA carboxylase deficiency (Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 467804). 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 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	Pathogenic	0.88
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.50
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.94	D;.
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.84	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.4	M;.
PhyloP100		9.3
PrimateAI	Benign	0.46	T
PROVEAN	Benign	-2.2	N;N
REVEL	Pathogenic	0.82
Sift	Uncertain	0.011	D;D
Sift4G	Uncertain	0.026	D;D
Polyphen		0.98	D;.
Vest4		0.69
MutPred		0.53		Loss of stability (P = 0.0435);.;
MVP		0.99
MPC		0.57
ClinPred		0.91	D
GERP RS		5.8
Varity_R		0.84
gMVP		0.92
Mutation Taster		=23/77	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: rs1554138549; hg19: chr5-70945972;