3-183017268-C-A

Variant names:

• chr3-183017268-C-A
• NM_020166.5:c.2047G>T
• MCCC1 p.Glu683*

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PVS1_Strong PM2 PP3

The NM_020166.5(MCCC1):​c.2047G>T​(p.Glu683*) variant causes a stop gained, splice region change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 33)
• Consequence: MCCC1 NM_020166.5 stop_gained, splice_region
• Scores: Splicing: ADA: 0.9904
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 6.04
• Publications: 0 publications found

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-AS1 (HGNC:40366): (MCCC1 antisense RNA 1)

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 4 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020166.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MCCC1	NM_020166.5	MANE Select	c.2047G>T	p.Glu683*	stop_gained splice_region	Exon 18 of 19	NP_064551.3
	MCCC1	NM_001363880.1		c.1720G>T	p.Glu574*	stop_gained splice_region	Exon 17 of 18	NP_001350809.1	E9PHF7
	MCCC1	NM_001293273.2		c.1696G>T	p.Glu566*	stop_gained splice_region	Exon 16 of 17	NP_001280202.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MCCC1	ENST00000265594.9	TSL:1 MANE Select	c.2047G>T	p.Glu683*	stop_gained splice_region	Exon 18 of 19	ENSP00000265594.4	Q96RQ3
	MCCC1	ENST00000492597.5	TSL:1	c.1720G>T	p.Glu574*	stop_gained splice_region	Exon 17 of 18	ENSP00000419898.1	E9PHF7
	MCCC1	ENST00000497830.5	TSL:1	n.*1644G>T		splice_region non_coding_transcript_exon	Exon 16 of 17	ENSP00000420088.1	F2Z3E2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.66
CADD	Pathogenic	52
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		6.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=3/197	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Pathogenic	0.89
SpliceAI score (max)		0.15		Details are displayed if max score is > 0.2

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr3-182735056;