11-102579053-G-A

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2PP3

The NM_004771.4(MMP20):c.1337C>T(p.Ala446Val) variant causes a missense change. The variant allele was found at a frequency of 0.000000686 in 1,457,126 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 Uncertain significance (★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

MMP20
NM_004771.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 5.65

Publications

0 publications found

Variant links:

Genes affected

MMP20 (HGNC:7167): (matrix metallopeptidase 20) Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Most MMP's are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. The protein encoded by this gene degrades amelogenin, the major protein component of dental enamel matrix, and thus thought to play a role in tooth enamel formation. A mutation in this gene, which alters the normal splice pattern and results in premature termination of the encoded protein, has been associated with amelogenesis imperfecta. This gene is part of a cluster of MMP genes located on chromosome 11q22.3. [provided by RefSeq, Aug 2011]

MMP20 Gene-Disease associations (from GenCC):

amelogenesis imperfecta hypomaturation type 2A2
Inheritance: AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
amelogenesis imperfecta type 2
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

MMP20 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.795

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MMP20	NM_004771.4 link	c.1337C>T	p.Ala446Val	missense_variant	Exon 9 of 10	ENST00000260228.3	NP_004762.2	O60882

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMP20	ENST00000260228.3 link	c.1337C>T	p.Ala446Val	missense_variant	Exon 9 of 10	1	NM_004771.4	ENSP00000260228.2		O60882
MMP20	ENST00000542305.1 link	n.235C>T		non_coding_transcript_exon_variant	Exon 2 of 3	2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.86e-7

AC:

AN:

1457126

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

725296

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33386

American (AMR)

AF:

0.00

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26096

East Asian (EAS)

AF:

0.00

AC:

AN:

39632

South Asian (SAS)

AF:

0.00

AC:

AN:

86156

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53364

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

9.03e-7

AC:

AN:

1107776

Other (OTH)

AF:

0.00

AC:

AN:

60236

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Mar 22, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.1337C>T (p.A446V) alteration is located in exon 9 (coding exon 9) of the MMP20 gene. This alteration results from a C to T substitution at nucleotide position 1337, causing the alanine (A) at amino acid position 446 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.29

BayesDel_addAF

Benign

-0.046

BayesDel_noAF

Benign

-0.30

CADD

Benign

(source)

DANN

Uncertain

0.98

DEOGEN2

Benign

0.029

Eigen

Uncertain

0.35

Eigen_PC

Uncertain

0.42

FATHMM_MKL

Uncertain

0.96

LIST_S2

Benign

0.72

M_CAP

Benign

0.0084

MetaRNN

Pathogenic

0.80

MetaSVM

Benign

-1.1

MutationAssessor

Benign

0.70

PhyloP100

5.7

PrimateAI

Uncertain

0.57

PROVEAN

Benign

0.44

REVEL

Benign

0.21

Sift

Benign

1.0

Sift4G

Benign

1.0

Polyphen

0.95

Vest4

0.73

MutPred

0.75

Loss of helix (P = 0.2022);

MVP

0.56

MPC

0.15

ClinPred

0.90

GERP RS

5.1

Varity_R

0.20

gMVP

0.76

Mutation Taster

=71/29

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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11-102579053-G-A

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over