4-653904-G-C

Variant names:

• chr4-653904-G-C
• rs1735846674
• NM_000283.4:c.764G>C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000283.4(PDE6B):​c.764G>C​(p.Arg255Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,194 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 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.57

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-AS1 (HGNC:40438): (PDE6B antisense RNA 1)

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a domain GAF 2 (size 177) in uniprot entity PDE6B_HUMAN there are 19 pathogenic changes around while only 1 benign (95%) in NM_000283.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.857

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PDE6B	NM_000283.4	c.764G>C	p.Arg255Thr	missense_variant	Exon 4 of 22	ENST00000496514.6	NP_000274.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PDE6B	ENST00000496514.6	c.764G>C	p.Arg255Thr	missense_variant	Exon 4 of 22	1	NM_000283.4	ENSP00000420295.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152194 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152194 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74342

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jan 15, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with threonine, which is neutral and polar, at codon 255 of the PDE6B protein (p.Arg255Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with PDE6B-related conditions. ClinVar contains an entry for this variant (Variation ID: 851144). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on PDE6B protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Pathogenic	31
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.70	.;D
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D
M_CAP	Benign	0.059	D
MetaRNN	Pathogenic	0.86	D;D
MetaSVM	Uncertain	-0.27	T
MutationAssessor	Benign	1.6	L;L
PrimateAI	Pathogenic	0.82	D
PROVEAN	Uncertain	-4.1	D;D
REVEL	Pathogenic	0.65
Sift	Benign	0.10	T;T
Sift4G	Benign	0.22	T;T
Polyphen		1.0	D;D
Vest4		0.90
MutPred		0.48		Gain of helix (P = 0.005);Gain of helix (P = 0.005);
MVP		0.93
MPC		0.70
ClinPred		0.98	D
GERP RS		5.3
Varity_R		0.52
gMVP		0.65

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: rs1735846674; hg19: chr4-647693;