1-147908217-C-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_005267.5(GJA8):c.262C>T(p.Pro88Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P88L) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GJA8 NM_005267.5 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.84

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 12 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_005267.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-147908217-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 650108.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995
• PP5: Variant 1-147908217-C-T is Pathogenic according to our data. Variant chr1-147908217-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 8721.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr1-147908217-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GJA8	NM_005267.5	c.262C>T	p.Pro88Ser	missense_variant	2/2	ENST00000369235.2
GJA8	XM_011509417.3	c.262C>T	p.Pro88Ser	missense_variant	1/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GJA8	ENST00000369235.2	c.262C>T	p.Pro88Ser	missense_variant	2/2		NM_005267.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Cataract 1 multiple types Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	Mar 01, 1998	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Nov 26, 2019	For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Pro88 amino acid residue in GJA8. Other variant(s) that disrupt this residue have been determined to be pathogenic (Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. This variant has been reported to affect GJA8 protein function (PMID: 10362609, 12800976, 19073179). This variant has been observed in individual(s) with congenital cataracts (PMID: 9497259). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 8721). This variant is not present in population databases (ExAC no frequency). This sequence change replaces proline with serine at codon 88 of the GJA8 protein (p.Pro88Ser). The proline residue is highly conserved and there is a moderate physicochemical difference between proline and serine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
Cadd	Pathogenic	28
Dann	Pathogenic	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	1.0	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.6	H
MutationTaster	Benign	1.0	A;A
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-8.0	D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.92
MutPred		0.94		Gain of catalytic residue at P88 (P = 0.0187);
MVP		0.96
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.96
gMVP		0.99

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: rs80358200; hg19: chr1-147380344;