4-625629-G-T

Variant names:

• chr4-625629-G-T
• rs1734048235
• NM_000283.4:c.3G>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The NM_000283.4(PDE6B):​c.3G>T​(p.Met1?) variant causes a start lost change. The variant allele was found at a frequency of 0.00000657 in 152,224 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: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: PDE6B NM_000283.4 start_lost
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.60
• Publications: 0 publications found

Genes affected

PDE6B (HGNC:8786): (phosphodiesterase 6B) Photon absorption triggers a signaling cascade in rod photoreceptors that activates cGMP phosphodiesterase (PDE), resulting in the rapid hydrolysis of cGMP, closure of cGMP-gated cation channels, and hyperpolarization of the cell. PDE is a peripheral membrane heterotrimeric enzyme made up of alpha, beta, and gamma subunits. This gene encodes the beta subunit. Mutations in this gene result in retinitis pigmentosa and autosomal dominant congenital stationary night blindness. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Feb 2009]

PDE6B Gene-Disease associations (from GenCC):

• retinitis pigmentosa 40

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Laboratory for Molecular Medicine
• congenital stationary night blindness autosomal dominant 2

  Inheritance: AD Classification: STRONG, LIMITED Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• congenital stationary night blindness

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• retinitis pigmentosa

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 5 pathogenic variants. Next in-frame start position is after 66 codons. Genomic position: 625822. Lost 0.076 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PDE6B	NM_000283.4	c.3G>T	p.Met1?	start_lost	Exon 1 of 22	ENST00000496514.6	NP_000274.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PDE6B	ENST00000496514.6	c.3G>T	p.Met1?	start_lost	Exon 1 of 22	1	NM_000283.4	ENSP00000420295.1
PDE6B	ENST00000255622.10	c.3G>T	p.Met1?	start_lost	Exon 1 of 22	1		ENSP00000255622.6

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152224 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152224 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74364

African (AFR) AF: 0.00 AC: 0 AN: 41470

American (AMR) AF: 0.0000654 AC: 1 AN: 15288

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10628

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68024

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Oct 04, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Disruption of the initiator codon has been observed in individuals affected with inherited retinal disease (PMID: 28912962, 28041643, 28559085). This variant is not present in population databases (ExAC no frequency). This sequence change affects the initiator methionine of the PDE6B mRNA. The next in-frame methionine is located at codon 66. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.040
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.32	.;T
Eigen	Uncertain	0.57
Eigen_PC	Uncertain	0.54
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.90	D;D
M_CAP	Uncertain	0.25	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Uncertain	-0.24	T
PhyloP100		5.6
PROVEAN	Benign	-1.2	N;N
REVEL	Uncertain	0.38
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		0.98	D;D
Vest4		0.88
MutPred		0.96		Gain of catalytic residue at M1 (P = 0.0368);Gain of catalytic residue at M1 (P = 0.0368);
MVP		0.87
ClinPred		1.0	D
GERP RS		5.0
PromoterAI		0.0023	Neutral
Varity_R		0.81
gMVP		0.49
Mutation Taster		=5/195	disease causing

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: rs1734048235; hg19: chr4-619418;