rs1555339543

Variant names:

• chr13-20143270-G-C
• rs1555339543
• NM_021954.4:c.19C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_021954.4(GJA3):​c.19C>G​(p.Leu7Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic 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. L7P) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: GJA3 NM_021954.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.58
• Publications: 0 publications found

Genes affected

GJA3 (HGNC:4277): (gap junction protein alpha 3) The protein encoded by this gene is a connexin and is a component of lens fiber gap junctions. Defects in this gene are a cause of zonular pulverulent cataract type 3 (CZP3). [provided by RefSeq, Jan 2010]

GJA3 Gene-Disease associations (from GenCC):

• cataract 14 multiple types

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• early-onset nuclear cataract

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• early-onset posterior polar cataract

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• pulverulent cataract

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000299362 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_021954.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 27 curated pathogenic missense variants (we use a threshold of 10). The gene has 6 curated benign missense variants. Gene score misZ: 1.7112 (below the threshold of 3.09). Trascript score misZ: -0.026578 (below the threshold of 3.09). GenCC associations: The gene is linked to early-onset nuclear cataract, pulverulent cataract, early-onset posterior polar cataract, cataract 14 multiple types.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.961

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GJA3	NM_021954.4	c.19C>G	p.Leu7Val	missense_variant	Exon 2 of 2	ENST00000241125.4	NP_068773.2
GJA3	XM_011535048.3	c.19C>G	p.Leu7Val	missense_variant	Exon 2 of 2		XP_011533350.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GJA3	ENST00000241125.4	c.19C>G	p.Leu7Val	missense_variant	Exon 2 of 2	3	NM_021954.4	ENSP00000241125.3
ENSG00000299362	ENST00000762843.1	n.133+5268G>C		intron_variant	Intron 1 of 1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cataract 14 multiple types Uncertain:1

Jul 24, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. This variant has been observed in individual(s) with congenital cataracts (Invitae). This variant is not present in population databases (ExAC no frequency). This sequence change replaces leucine with valine at codon 7 of the GJA3 protein (p.Leu7Val). The leucine residue is highly conserved and there is a small physicochemical difference between leucine and valine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.32
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D
Eigen	Uncertain	0.51
Eigen_PC	Uncertain	0.41
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.7	M
PhyloP100		3.6
PrimateAI	Pathogenic	0.81	D
PROVEAN	Uncertain	-2.4	N
REVEL	Pathogenic	0.85
Sift	Uncertain	0.0030	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.65
MutPred		0.83		Gain of catalytic residue at G2 (P = 0.0137);
MVP		0.87
MPC		2.1
ClinPred		0.97	D
GERP RS		2.9
Varity_R		0.45
gMVP		0.96
Mutation Taster		=52/48	polymorphism

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: rs1555339543; hg19: chr13-20717409;