NM_022132.5:c.568C>T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1PM2PM5PP3_StrongPP5

The NM_022132.5(MCCC2):c.568C>T(p.His190Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000105 in 1,613,966 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H190R) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000089 ( 0 hom. )

Consequence

MCCC2
NM_022132.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:6U:1

Conservation

PhyloP100: 7.62

Publications

4 publications found

Variant links:

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

MCCC2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 11 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_022132.5

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr5-71604413-A-G is described in ClinVar as Pathogenic. ClinVar VariationId is 1926.Status of the report is no_assertion_criteria_provided, 0 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.986

PP5

Variant 5-71604412-C-T is Pathogenic according to our data. Variant chr5-71604412-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 198252.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MCCC2	NM_022132.5 link	c.568C>T	p.His190Tyr	missense_variant	Exon 6 of 17	ENST00000340941.11	NP_071415.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MCCC2	ENST00000340941.11 link	c.568C>T	p.His190Tyr	missense_variant	Exon 6 of 17	1	NM_022132.5	ENSP00000343657.6

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152090

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251464

AF XY:

0.0000147

show subpopulations

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:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000889

AC:

AN:

1461876

Hom.:

Cov.:

AF XY:

0.0000124

AC XY:

AN XY:

727236

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000812

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000360

AC:

AN:

1112000

Other (OTH)

AF:

0.0000331

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.421

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152090

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74306

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41408

American (AMR)

AF:

0.00

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10594

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000588

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000127

Hom.:

Bravo

AF:

0.0000264

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:6Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

3-methylcrotonyl-CoA carboxylase 2 deficiency

Pathogenic:2Uncertain:1

Oct 15, 2018

SIB Swiss Institute of Bioinformatics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:curation

This variant is interpreted as Likely Pathogenic, for MCC2 deficiency, autosomal recessive. The following ACMG Tag(s) were applied: PM2 => Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium. PP3 => Multiple lines of computational evidence support a deleterious effect on the gene or gene product. PS3 => Well-established functional studies show a deleterious effect (https://www.ncbi.nlm.nih.gov/pubmed/16010683). -

Nov 29, 2023

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Sep 01, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces histidine with tyrosine at codon 190 of the MCCC2 protein (p.His190Tyr). The histidine residue is highly conserved and there is a moderate physicochemical difference between histidine and tyrosine. This variant is present in population databases (rs773774134, ExAC 0.001%). This missense change has been observed in individual(s) with 3-methylcrotonyl-CoA carboxylase deficiency (PMID: 16010683). ClinVar contains an entry for this variant (Variation ID: 198252). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects MCCC2 function (PMID: 16010683). This variant disrupts the p.His190 amino acid residue in MCCC2. Other variant(s) that disrupt this residue have been observed in individuals with MCCC2-related conditions (PMID: 16010683, 17968484), which suggests that this may be a clinically significant amino acid residue. 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. -

not provided

Pathogenic:2

May 04, 2015

Eurofins Ntd Llc (ga)

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Sep 20, 2018

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The H190Y variant in the MCCC2 gene has been reported previously in association with 3-methylcrotonyl-CoA carboxylase deficiency, in an affected individual who was homozygous for the H190Y variant (Dantas et al., 2005). This variant is not observed at a significant frequency in large population cohorts (Lek et al., 2016). The H190Y variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. In-silico analyses, including protein predictors and evolutionary conservation, support a deleterious effect, and expression studies found that H190Y is associated with severely decreased 3-methylcrotonyl-CoA carboxylase activity (Dantas et al., 2005). Missense variants in the same codon (H190R) and nearby residues (R193C and R193H) have been reported in the Human Gene Mutation Database in association with 3-methylcrotonyl-CoA carboxylase deficiency (Stenson et al., 2014), supporting the functional importance of this region of the protein. We interpret H190Y as a pathogenic variant. -

Methylcrotonyl-CoA carboxylase deficiency

Pathogenic:1

Jun 13, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: MCCC2 c.568C>T (p.His190Tyr) results in a conservative amino acid change located in the Acetyl-coenzyme A carboxyltransferase, N-terminal domain (IPR011762) of the encoded protein sequence. 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. The variant allele was found at a frequency of 1.6e-05 in 251464 control chromosomes. c.568C>T has been observed in individual(s) affected with Methylcrotonyl-CoA Carboxylase Deficiency (e.g. Dantas_2005, Mao_2020). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function in-vitro and found that the variant results in an absence of normal 3-methylcrotonyl-CoA carboxylase (MCC) activity (Dantas_2005). The following publications have been ascertained in the context of this evaluation (PMID: 16010683, 33058845). ClinVar contains an entry for this variant (Variation ID: 198252). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

MCCC2-related disorder

Pathogenic:1

Jul 15, 2024

PreventionGenetics, part of Exact Sciences

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

The MCCC2 c.568C>T variant is predicted to result in the amino acid substitution p.His190Tyr. This variant was reported in the homozygous state in one mildly affected individual with 3-methylcrotonyl-CoA carboxylase deficiency (Dantas et al 2005. PubMed ID: 16010683). In an in vitro expression study, the p.His190Tyr substitution was reported to abolish enzyme activity (Dantas et al 2005. PubMed ID: 16010683). An alternative substitution of the same amino acid (p.His190Arg) was reported along with a second likely pathogenic MCCC2 variant in an individual with 3-methylcrotonyl-CoA carboxylase deficiency (Uematsu et al. 2007. PubMed ID: 17968484). This variant is reported in 0.0033% of alleles in individuals of South Asian descent in gnomAD. This variant is interpreted as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.45

BayesDel_addAF

Pathogenic

0.49

BayesDel_noAF

Pathogenic

0.56

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.78

D;D;.

Eigen

Pathogenic

0.96

Eigen_PC

Pathogenic

0.89

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.99

D;D;D

M_CAP

Pathogenic

0.33

MetaRNN

Pathogenic

0.99

D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

2.9

.;M;.

PhyloP100

7.6

PrimateAI

Uncertain

0.55

PROVEAN

Pathogenic

-5.7

.;D;D

REVEL

Pathogenic

0.97

Sift

Pathogenic

0.0

.;D;D

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0, 0.92

.;D;P

Vest4

0.96

MutPred

0.91

Loss of catalytic residue at R188 (P = 0.0595);Loss of catalytic residue at R188 (P = 0.0595);Loss of catalytic residue at R188 (P = 0.0595);

MVP

0.99

MPC

0.56

ClinPred

0.97

GERP RS

5.6

Varity_R

0.94

gMVP

0.92

Mutation Taster

=4/96

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over