2-149579643-G-A

Position:

• chr2-149579643-G-A

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_015702.3(MMADHC):​c.160C>T​(p.Arg54Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,202 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 Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. R54R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MMADHC NM_015702.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:2 O:1
• Conservation: PhyloP100: 3.03

Genes affected

MMADHC (HGNC:25221): (metabolism of cobalamin associated D) This gene encodes a mitochondrial protein that is involved in an early step of vitamin B12 metabolism. Vitamin B12 (cobalamin) is essential for normal development and survival in humans. Mutations in this gene cause methylmalonic aciduria and homocystinuria type cblD (MMADHC), a disorder of cobalamin metabolism that is characterized by decreased levels of the coenzymes adenosylcobalamin and methylcobalamin. Pseudogenes have been identified on chromosomes 11 and X.[provided by RefSeq, Nov 2008]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-149579643-G-A is Pathogenic according to our data. Variant chr2-149579643-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 765.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MMADHC	NM_015702.3	c.160C>T	p.Arg54Ter	stop_gained	4/8	ENST00000303319.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MMADHC	ENST00000303319.10	c.160C>T	p.Arg54Ter	stop_gained	4/8	1	NM_015702.3	P1
MMADHC	ENST00000422782.2	c.160C>T	p.Arg54Ter	stop_gained	4/9	5
MMADHC	ENST00000428879.5	c.160C>T	p.Arg54Ter	stop_gained	3/7	2		P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461202 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 726892

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Methylmalonic aciduria and homocystinuria type cblD Pathogenic:1 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Aug 24, 2023	- -
not provided, no classification provided	literature only	GeneReviews	-	- -

METHYLMALONIC ACIDURIA, cblD TYPE Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Apr 03, 2008

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	38
DANN	Uncertain	1.0
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.24
FATHMM_MKL	Uncertain	0.88	D
MutationTaster	Benign	1.0	A;A;A
Vest4		0.52
GERP RS		2.6

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

LitVar

Other links and lift over

dbSNP: rs118204047; hg19: chr2-150436157; COSMIC: COSV57574342;