chr11-102576899-T-A

Variant names:

• chr11-102576899-T-A
• rs2292729
• NM_004771.4:c.*427A>T

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_Strong BS1_Supporting

The NM_004771.4(MMP20):​c.*427A>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000394 in 152,300 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 Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000039 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: MMP20 NM_004771.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.698
• Publications: 0 publications found

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

ACMG classification

Our verdict: Likely_benign. The variant received -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.79).
• BS1: Variant frequency is greater than expected in population eas. GnomAd4 allele frequency = 0.0000394 (6/152300) while in subpopulation EAS AF = 0.00116 (6/5192). AF 95% confidence interval is 0.000502. There are 0 homozygotes in GnomAd4. There are 0 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MMP20	NM_004771.4	c.*427A>T		3_prime_UTR_variant	Exon 10 of 10	ENST00000260228.3	NP_004762.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMP20	ENST00000260228.3	c.*427A>T		3_prime_UTR_variant	Exon 10 of 10	1	NM_004771.4	ENSP00000260228.2
MMP20	ENST00000542305.1	n.*245A>T		downstream_gene_variant		2

Frequencies

GnomAD3 genomes AF: 0.0000394 AC: 6 AN: 152182 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00115

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 20478 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 10790

African (AFR) AF: 0.00 AC: 0 AN: 104

American (AMR) AF: 0.00 AC: 0 AN: 2742

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 286

East Asian (EAS) AF: 0.00 AC: 0 AN: 1098

South Asian (SAS) AF: 0.00 AC: 0 AN: 2998

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 602

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 42

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 11718

Other (OTH) AF: 0.00 AC: 0 AN: 888

GnomAD4 genome AF: 0.0000394 AC: 6 AN: 152300 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74468

African (AFR) AF: 0.00 AC: 0 AN: 41558

American (AMR) AF: 0.00 AC: 0 AN: 15302

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00116 AC: 6 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10610

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68018

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000869

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Amelogenesis imperfecta hypomaturation type 2A2 Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
CADD	Benign	4.8
DANN	Benign	0.64
PhyloP100		0.70

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: rs2292729; hg19: chr11-102447630;