rs1553957939

Variant names:

• chr4-145639578-GGTCA-G
• rs1553957939
• NM_172250.3:c.439+4_439+7delAGTC

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM2 PP3_Moderate PP5_Very_Strong

The NM_172250.3(MMAA):​c.439+4_439+7delAGTC variant causes a splice region, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000757 in 1,453,972 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000076 (0 hom.)
• Consequence: MMAA NM_172250.3 splice_region, intron
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:3 U:1
• Conservation: PhyloP100: 9.60
• Publications: 1 publications found

Genes affected

MMAA (HGNC:18871): (metabolism of cobalamin associated A) The protein encoded by this gene is involved in the translocation of cobalamin into the mitochondrion, where it is used in the final steps of adenosylcobalamin synthesis. Adenosylcobalamin is a coenzyme required for the activity of methylmalonyl-CoA mutase. Defects in this gene are a cause of methylmalonic aciduria. [provided by RefSeq, Jul 2008]

MMAA Gene-Disease associations (from GenCC):

• methylmalonic aciduria, cblA type

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Myriad Women’s Health, Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet, G2P

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 4-145639578-GGTCA-G is Pathogenic according to our data. Variant chr4-145639578-GGTCA-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 549964.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_172250.3. 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
	MMAA	NM_172250.3	MANE Select	c.439+4_439+7delAGTC		splice_region intron	N/A	NP_758454.1
	MMAA	NM_001375644.1		c.439+4_439+7delAGTC		splice_region intron	N/A	NP_001362573.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MMAA	ENST00000649156.2	MANE Select	c.439+4_439+7delAGTC		splice_region intron	N/A	ENSP00000497008.1
	MMAA	ENST00000511969.4	TSL:1	n.439+4_439+7delAGTC		splice_region intron	N/A	ENSP00000427422.1
	MMAA	ENST00000541599.5	TSL:5	c.439+4_439+7delAGTC		splice_region intron	N/A	ENSP00000442284.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000757 AC: 11 AN: 1453972 Hom.: 0 AF XY: 0.00000554 AC XY: 4 AN XY: 721994

African (AFR) AF: 0.00 AC: 0 AN: 33138

American (AMR) AF: 0.00 AC: 0 AN: 43990

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25962

East Asian (EAS) AF: 0.00 AC: 0 AN: 39524

South Asian (SAS) AF: 0.00 AC: 0 AN: 84822

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53308

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5690

European-Non Finnish (NFE) AF: 0.00000903 AC: 10 AN: 1107482

Other (OTH) AF: 0.0000167 AC: 1 AN: 60056

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

ClinVar submissions as Germline

Significance: Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
3	1	-	Methylmalonic aciduria, cblA type (4)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.6
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.82		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.82		Position offset: 0

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

Other links and lift over

dbSNP: rs1553957939; hg19: chr4-146560730;