22-32859225-G-T

Position:

• chr22-32859225-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The NM_000362.5(TIMP3):​c.484G>T​(p.Glu162*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,886 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: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TIMP3 NM_000362.5 stop_gained
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 10.0

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]

SYN3 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 18 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TIMP3	NM_000362.5	c.484G>T	p.Glu162*	stop_gained	5/5	ENST00000266085.7	NP_000353.1
SYN3	NM_003490.4	c.711+5690C>A		intron_variant		ENST00000358763.7	NP_003481.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TIMP3	ENST00000266085.7	c.484G>T	p.Glu162*	stop_gained	5/5	1	NM_000362.5	ENSP00000266085.5
SYN3	ENST00000358763.7	c.711+5690C>A		intron_variant		5	NM_003490.4	ENSP00000351614.2
SYN3	ENST00000462268.1	n.225+5690C>A		intron_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461886 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727248

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Sorsby fundus dystrophy Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Sep 01, 2000

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 16, 2021

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. Experimental studies have shown that this variant affects TIMP3 protein function (PMID: 10854443). This variant has been observed in individual(s) with Sorsby fundus dystrophy (PMID: 10854443). It has also been observed to segregate with disease in related individuals. This is also known as E139X. ClinVar contains an entry for this variant (Variation ID: 12680). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Glu162*) in the TIMP3 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 50 amino acid(s) of the TIMP3 protein. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.64	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	40
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.97	D
Vest4		0.81
ClinPred		1.0	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs137853302; hg19: chr22-33255212;