rs138794621

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_020166.5(MCCC1):c.873G>A(p.Ala291=) variant causes a splice region, synonymous change. The variant allele was found at a frequency of 0.0000282 in 1,597,604 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000026 ( 1 hom. )

Consequence

MCCC1
NM_020166.5 splice_region, synonymous

Scores

Splicing: ADA: 1.000

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 4.72

Variant links:

Genes affected

MCCC1 (HGNC:6936): (methylcrotonyl-CoA carboxylase subunit 1) This gene encodes the large 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. [provided by RefSeq, Jul 2008]

MCCC1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MCCC1	NM_020166.5 linkuse as main transcript	c.873G>A	p.Ala291=	splice_region_variant, synonymous_variant	8/19	ENST00000265594.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MCCC1	ENST00000265594.9 linkuse as main transcript	c.873G>A	p.Ala291=	splice_region_variant, synonymous_variant	8/19	1	NM_020166.5	P1

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152140

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000169

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000262

AC:

AN:

228920

Hom.:

AF XY:

0.0000163

AC XY:

AN XY:

123012

show subpopulations

Gnomad AFR exome

AF:

0.000275

Gnomad AMR exome

AF:

0.00

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:

0.0000199

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000263

AC:

AN:

1445464

Hom.:

Cov.:

AF XY:

0.0000265

AC XY:

AN XY:

717510

show subpopulations

Gnomad4 AFR exome

AF:

0.0000903

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000119

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000281

Gnomad4 OTH exome

AF:

0.0000335

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152140

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74334

show subpopulations

Gnomad4 AFR

AF:

0.000169

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000155

Hom.:

Bravo

AF:

0.0000416

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Methylcrotonyl-CoA carboxylase deficiency

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Sep 16, 2020

- -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 03, 2021

The c.873G>A (p.A291A) alteration is located in exon 8 (coding exon 8) of the MCCC1 gene. This alteration consists of a G to A substitution at nucleotide position 873. This nucleotide substitution does not change the alanine at codon 291. However, this change occurs in the last base pair of coding exon 8, which makes it likely to have some effect on normal mRNA splicing. In silico splice site analysis predicts that this alteration may weaken the native splice donor site and will result in the creation or strengthening of a novel splice donor site. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Jan 25, 2018

- -

3-methylcrotonyl-CoA carboxylase 1 deficiency

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 14, 2022

This sequence change affects codon 291 of the MCCC1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MCCC1 protein. This variant also falls at the last nucleotide of exon 8, which is part of the consensus splice site for this exon. This variant is present in population databases (rs138794621, gnomAD 0.02%). This variant has been observed in individual(s) with MCCC1-related conditions (PMID: 30626930). ClinVar contains an entry for this variant (Variation ID: 167271). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.11

Cadd

Pathogenic

Dann

Benign

0.95

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.99

SpliceAI score (max)

0.73

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.73

Position offset: -23

DS_DL_spliceai

0.44

Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over