chr22-32802053-G-T

Position:

• chr22-32802053-G-T

Variant summary

Our verdict is Benign. Variant got -7 ACMG points: 0P and 7B. BP4_Moderate BS1_Supporting BS2

The NM_000362.5(TIMP3):​c.52G>T​(p.Asp18Tyr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000491 in 1,424,800 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D18G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000049 (0 hom.)
• Consequence: TIMP3 NM_000362.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.224

Genes affected

TIMP3 (HGNC:11822): (TIMP metallopeptidase inhibitor 3) This gene belongs to the TIMP gene family. The proteins encoded by this gene family are inhibitors of the matrix metalloproteinases, a group of peptidases involved in degradation of the extracellular matrix (ECM). Expression of this gene is induced in response to mitogenic stimulation and this netrin domain-containing protein is localized to the ECM. Mutations in this gene have been associated with the autosomal dominant disorder Sorsby's fundus dystrophy. [provided by RefSeq, Jul 2008]

SYN3 (HGNC:11496): (synapsin III) This gene is a member of the synapsin gene family. Synapsins encode neuronal phosphoproteins which associate with the cytoplasmic surface of synaptic vesicles. Family members are characterized by common protein domains, and they are implicated in synaptogenesis and the modulation of neurotransmitter release, suggesting a potential role in several neuropsychiatric diseases. The protein encoded by this gene shares the synapsin family domain model, with domains A, C, and E exhibiting the highest degree of conservation. The protein contains a unique domain J, located between domains C and E. Based on this gene's localization to 22q12.3, a possible schizophrenia susceptibility locus, and the established neurobiological roles of the synapsins, this family member may represent a candidate gene for schizophrenia. The TIMP3 gene is located within an intron of this gene and is transcribed in the opposite direction. Alternative splicing of this gene results in multiple splice variants that encode different isoforms. [provided by RefSeq, Oct 2008]

ACMG classification

Verdict is Benign. Variant got -7 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.10564551).
• BS1: Variant frequency is greater than expected in population mid. gnomad4_exome allele frequency = 0.00000491 (7/1424800) while in subpopulation MID AF= 0.000349 (2/5734). AF 95% confidence interval is 0.0000613. There are 0 homozygotes in gnomad4_exome. There are 3 alleles in male gnomad4_exome subpopulation. Median coverage is 31. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAdExome4 at 7 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TIMP3	NM_000362.5	c.52G>T	p.Asp18Tyr	missense_variant	1/5	ENST00000266085.7
SYN3	NM_003490.4	c.711+62862C>A		intron_variant		ENST00000358763.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TIMP3	ENST00000266085.7	c.52G>T	p.Asp18Tyr	missense_variant	1/5	1	NM_000362.5	P1
SYN3	ENST00000358763.7	c.711+62862C>A		intron_variant		5	NM_003490.4	P1
SYN3	ENST00000462268.1	n.225+62862C>A		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000111 AC: 2 AN: 180142 Hom.: 0 AF XY: 0.0000202 AC XY: 2 AN XY: 99096

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000710

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000129

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000491 AC: 7 AN: 1424800 Hom.: 0 Cov.: 31 AF XY: 0.00000425 AC XY: 3 AN XY: 706220

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000525

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000233

Gnomad4 NFE exome AF: 9.11e-7

Gnomad4 OTH exome AF: 0.0000169

GnomAD4 genome Cov.: 32

Bravo AF: 0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 18, 2021

This variant has not been reported in the literature in individuals affected with TIMP3-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The tyrosine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. This sequence change replaces aspartic acid with tyrosine at codon 18 of the TIMP3 protein (p.Asp18Tyr). The aspartic acid residue is weakly conserved and there is a large physicochemical difference between aspartic acid and tyrosine. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.085
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.24
CADD	Benign	5.7
DANN	Benign	0.94
DEOGEN2	Benign	0.28	T
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.0
FATHMM_MKL	Benign	0.24	N
LIST_S2	Benign	0.41	T
M_CAP	Uncertain	0.20	D
MetaRNN	Benign	0.11	T
MetaSVM	Benign	-0.38	T
MutationAssessor	Benign	1.6	L
MutationTaster	Benign	1.0	D;D;N;N
PrimateAI	Uncertain	0.48	T
PROVEAN	Benign	-1.7	N
REVEL	Uncertain	0.31
Sift	Benign	0.20	T
Sift4G	Benign	0.065	T
Polyphen		0.0	B
Vest4		0.098
MutPred		0.30		Gain of helix (P = 0.062);
MVP		0.76
MPC		1.3
ClinPred		0.16	T
GERP RS		-4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.098
gMVP		0.48

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

LitVar

Other links and lift over

dbSNP: rs1324470172; hg19: chr22-33198039;