rs1553957883

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_172250.3(MMAA):​c.72C>A​(p.Tyr24*) 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 1,461,868 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 Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. Y24Y) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

MMAA
NM_172250.3 stop_gained

Scores

2
2
3

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 0.695

Publications

0 publications found
Variant links:
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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 117 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 4-145639211-C-A is Pathogenic according to our data. Variant chr4-145639211-C-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 440795.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
MMAANM_172250.3 linkc.72C>A p.Tyr24* stop_gained Exon 2 of 7 ENST00000649156.2 NP_758454.1 Q8IVH4
MMAANM_001375644.1 linkc.72C>A p.Tyr24* stop_gained Exon 2 of 7 NP_001362573.1
MMAAXM_011531684.4 linkc.72C>A p.Tyr24* stop_gained Exon 2 of 7 XP_011529986.1 Q8IVH4

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
MMAAENST00000649156.2 linkc.72C>A p.Tyr24* stop_gained Exon 2 of 7 NM_172250.3 ENSP00000497008.1 Q8IVH4

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1461868
Hom.:
0
Cov.:
32
AF XY:
0.00000138
AC XY:
1
AN XY:
727232
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26132
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39696
South Asian (SAS)
AF:
0.0000232
AC:
2
AN:
86256
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:
0.00
AC:
0
AN:
1112000
Other (OTH)
AF:
0.00
AC:
0
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.450
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Methylmalonic aciduria, cblA type Pathogenic:4
Jan 28, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Tyr24*) in the MMAA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MMAA are known to be pathogenic (PMID: 15523652, 15781192). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with clinical features of MMACblA (PMID: 27591164). ClinVar contains an entry for this variant (Variation ID: 440795). For these reasons, this variant has been classified as Pathogenic. -

Jun 04, 2024
Fulgent Genetics, Fulgent Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Sep 28, 2017
Counsyl
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

-
University Children's Hospital, University of Zurich
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Methylmalonic aciduria of the cblA complementation type Pathogenic:1
-
CENTOGENE GmbH and LLC - Guiding Precision Medicine
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.63
D
BayesDel_noAF
Pathogenic
0.60
CADD
Pathogenic
35
DANN
Uncertain
0.99
Eigen
Uncertain
0.34
Eigen_PC
Benign
0.11
FATHMM_MKL
Benign
0.35
N
PhyloP100
0.69
Vest4
0.69, 0.69
GERP RS
4.6
Mutation Taster
=9/191
disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1553957883; hg19: chr4-146560363; API