1-147908023-G-C

Position:

• chr1-147908023-G-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PP3_Strong PP5_Moderate

The NM_005267.5(GJA8):​c.68G>C​(p.Arg23Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,804 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R23G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GJA8 NM_005267.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 8.11

Genes affected

GJA8 (HGNC:4281): (gap junction protein alpha 8) This gene encodes a transmembrane connexin protein that is necessary for lens growth and maturation of lens fiber cells. The encoded protein is a component of gap junction channels and functions in a calcium and pH-dependent manner. Mutations in this gene have been associated with zonular pulverulent cataracts, nuclear progressive cataracts, and cataract-microcornea syndrome. [provided by RefSeq, Dec 2009]

ACMG classification

Verdict is Pathogenic. Variant got 10 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, 6 uncertain in NM_005267.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995
• PP5: Variant 1-147908023-G-C is Pathogenic according to our data. Variant chr1-147908023-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 8724.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr1-147908023-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GJA8	NM_005267.5	c.68G>C	p.Arg23Thr	missense_variant	2/2	ENST00000369235.2	NP_005258.2
GJA8	XM_011509417.3	c.68G>C	p.Arg23Thr	missense_variant	1/2		XP_011507719.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GJA8	ENST00000369235.2	c.68G>C	p.Arg23Thr	missense_variant	2/2	6	NM_005267.5	ENSP00000358238.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461804 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 727198

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: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Cataract 1 multiple types Pathogenic:2

Likely pathogenic, criteria provided, single submitter	curation	Dept. Genetics and Cancer, Menzies Institute for Medical Research, University of Tasmania	Jan 21, 2023	Variant identified and curated during a GJA8 specific review of the literature in relation to pediatric or congenital cataract. ACMG-AMP criteria applied: PP1(Strong), PM1(Supporting), PM2(Supporting), PP3. Original variant report: PMID:14627691. The cataract phenotype reported for this variant is: Nuclear. Gene review and curation guidelines are outlined in: https://doi.org/10.1080/17469899.2023.2160320 -
Pathogenic, no assertion criteria provided	literature only	OMIM	Nov 01, 2003	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	26
DANN	Uncertain	0.98
DEOGEN2	Pathogenic	0.97	D
Eigen	Pathogenic	0.76
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.90	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.5	M
PrimateAI	Pathogenic	0.85	D
PROVEAN	Uncertain	-3.5	D
REVEL	Pathogenic	0.94
Sift	Uncertain	0.0020	D
Sift4G	Uncertain	0.0040	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.96		Loss of MoRF binding (P = 0.0424);
MVP		0.95
ClinPred		0.99	D
GERP RS		5.0
Varity_R		0.90
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs80358203; hg19: chr1-147380150;