Genetic Variant MMAA:p.Ala99Pro (chr4-145639434-G-C) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_172250.3(MMAA):c.295G>C(p.Ala99Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A99T) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MMAA
NM_172250.3 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.64

Publications

1 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

MMAA links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.856

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MMAA	NM_172250.3 link	c.295G>C	p.Ala99Pro	missense_variant	Exon 2 of 7	ENST00000649156.2	NP_758454.1	Q8IVH4
MMAA	NM_001375644.1 link	c.295G>C	p.Ala99Pro	missense_variant	Exon 2 of 7		NP_001362573.1
MMAA	XM_011531684.4 link	c.295G>C	p.Ala99Pro	missense_variant	Exon 2 of 7		XP_011529986.1	Q8IVH4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMAA	ENST00000649156.2 link	c.295G>C	p.Ala99Pro	missense_variant	Exon 2 of 7		NM_172250.3	ENSP00000497008.1		Q8IVH4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461874

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727236

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112008

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<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.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.45

BayesDel_addAF

Pathogenic

0.43

BayesDel_noAF

Pathogenic

0.38

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.39

T;.;T;T;T;T

Eigen

Pathogenic

0.70

Eigen_PC

Pathogenic

0.67

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.97

.;D;.;.;D;D

M_CAP

Uncertain

0.19

MetaRNN

Pathogenic

0.86

D;D;D;D;D;D

MetaSVM

Pathogenic

0.85

MutationAssessor

Uncertain

2.8

M;.;M;M;M;.

PhyloP100

7.6

PrimateAI

Uncertain

0.55

PROVEAN

Uncertain

-2.9

.;.;D;.;.;.

REVEL

Pathogenic

0.82

Sift

Uncertain

0.020

.;.;D;.;.;.

Sift4G

Uncertain

0.045

.;.;D;.;.;D

Polyphen

1.0

D;.;D;D;D;.

Vest4

0.85, 0.87

MutPred

0.56

Gain of glycosylation at A99 (P = 0.1169);Gain of glycosylation at A99 (P = 0.1169);Gain of glycosylation at A99 (P = 0.1169);Gain of glycosylation at A99 (P = 0.1169);Gain of glycosylation at A99 (P = 0.1169);Gain of glycosylation at A99 (P = 0.1169);

MVP

0.76

MPC

0.39

ClinPred

0.98

GERP RS

4.6

Varity_R

0.91

gMVP

0.83

Mutation Taster

=192/108

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over