rs772395858

Variant names:

• chr3-183071122-T-C
• rs772395858
• NM_020166.5:c.640-2A>G

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1_Moderate PS3 PM2 PP5_Very_Strong

The NM_020166.5(MCCC1):​c.640-2A>G variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000219 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV000656959: Disruption of this splice site has been observed in individual(s) with 3-methylcrotonyl-CoA carboxylase deficiency (PMID:27601257" and additional evidence is available in ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000022 (0 hom.)
• Consequence: MCCC1 NM_020166.5 splice_acceptor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 7.58
• Publications: 1 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 Gene-Disease associations (from GenCC):

• 3-methylcrotonyl-CoA carboxylase 1 deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• 3-methylcrotonyl-CoA carboxylase deficiency

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.05601469 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.9, offset of -24, new splice context is: ttgttttatttatgttgtAGtca. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PS3: PS3 evidence extracted from ClinVar submissions: SCV000656959: Disruption of this splice site has been observed in individual(s) with 3-methylcrotonyl-CoA carboxylase deficiency (PMID: 27601257; internal data).
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-183071122-T-C is Pathogenic according to our data. Variant chr3-183071122-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 198578.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.640-2A>G		splice_acceptor intron	N/A	NP_064551.3
	MCCC1	NM_001363880.1		c.313-2A>G		splice_acceptor intron	N/A	NP_001350809.1	E9PHF7
	MCCC1	NM_001293273.2		c.289-2A>G		splice_acceptor intron	N/A	NP_001280202.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MCCC1	ENST00000265594.9	TSL:1 MANE Select	c.640-2A>G		splice_acceptor intron	N/A	ENSP00000265594.4	Q96RQ3
	MCCC1	ENST00000492597.5	TSL:1	c.313-2A>G		splice_acceptor intron	N/A	ENSP00000419898.1	E9PHF7
	MCCC1	ENST00000497830.5	TSL:1	n.*237-2A>G		splice_acceptor intron	N/A	ENSP00000420088.1	F2Z3E2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000795 AC: 2 AN: 251430 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000219 AC: 32 AN: 1461874 Hom.: 0 Cov.: 31 AF XY: 0.0000234 AC XY: 17 AN XY: 727240

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.0000224 AC: 1 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000270 AC: 30 AN: 1112002

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000280 Hom.: 0

Bravo AF: 0.0000151

ExAC AF: 0.0000165 AC: 2

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
4	-	-	3-methylcrotonyl-CoA carboxylase 1 deficiency (4)
1	-	-	Methylcrotonyl-CoA carboxylase deficiency (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.11
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		7.6
GERP RS		5.6
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.87		Position offset: -10
DS_AL_spliceai		1.0		Position offset: -2

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

Other links and lift over

dbSNP: rs772395858; hg19: chr3-182788910;