2-149579643-G-T

Variant names:

• chr2-149579643-G-T
• rs118204047
• NM_015702.3:c.160C>A

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Moderate BP6_Moderate BP7

The NM_015702.3(MMADHC):​c.160C>A​(p.Arg54Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,202 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MMADHC NM_015702.3 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 3.03
• Publications: 4 publications found

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]

MMADHC Gene-Disease associations (from GenCC):

• inborn disorder of cobalamin metabolism and transport

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen, Ambry Genetics
• methylmalonic aciduria and homocystinuria type cblD

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.38).
• BP6: Variant 2-149579643-G-T is Benign according to our data. Variant chr2-149579643-G-T is described in ClinVar as Likely_benign. ClinVar VariationId is 2916542.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=3.03 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_015702.3. 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
	MMADHC	NM_015702.3	MANE Select	c.160C>A	p.Arg54Arg	synonymous	Exon 4 of 8	NP_056517.1	Q9H3L0

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MMADHC	ENST00000303319.10	TSL:1 MANE Select	c.160C>A	p.Arg54Arg	synonymous	Exon 4 of 8	ENSP00000301920.5	Q9H3L0
	MMADHC	ENST00000934249.1		c.160C>A	p.Arg54Arg	synonymous	Exon 4 of 9	ENSP00000604308.1
	MMADHC	ENST00000422782.2	TSL:5	c.160C>A	p.Arg54Arg	synonymous	Exon 4 of 9	ENSP00000408331.2	F8WEC0

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461202 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726892

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33462

American (AMR) AF: 0.00 AC: 0 AN: 44630

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26124

East Asian (EAS) AF: 0.00 AC: 0 AN: 39678

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86186

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53362

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5738

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111664

Other (OTH) AF: 0.00 AC: 0 AN: 60358

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

ClinVar submissions

Significance: Likely benign

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	-	1	Methylmalonic aciduria and homocystinuria type cblD (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.38
CADD	Benign	11
DANN	Benign	0.63
PhyloP100		3.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2
Mutation Taster		=97/3	polymorphism

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

Other links and lift over

dbSNP: rs118204047; hg19: chr2-150436157;