17-76540146-G-A

Variant names:

• chr17-76540146-G-A
• rs121918369
• NM_001077620.3:c.5G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_001077620.3(PRCD):​c.5G>A​(p.Cys2Tyr) variant causes a missense change. 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 (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: PRCD NM_001077620.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 5.64
• Publications: 6 publications found

Genes affected

PRCD (HGNC:32528): (photoreceptor disc component) This gene is predominantly expressed in the retina, and mutations in this gene are the cause of autosomal recessive retinal degeneration in both humans and dogs. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Mar 2010]

CYGB (HGNC:16505): (cytoglobin) This gene encodes a globin protein found in vertebrate cells. The encoded protein is described as a hexacoordinate hemoglobin which binds ligand differently from the pentacoordinate hemoglobins involved in oxygen transport, and may be involved in protection during oxidative stress. This gene is located on chromosome 17 in the same region as a retinal gene which is mutated in progressive rod-cone degeneration, but in the opposite orientation. [provided by RefSeq, Jan 2012]

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a lipid_moiety_binding_region S-palmitoyl cysteine (size 0) in uniprot entity PRCD_HUMAN
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.947

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PRCD	NM_001077620.3	c.5G>A	p.Cys2Tyr	missense_variant	Exon 1 of 5	ENST00000592014.6	NP_001071088.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PRCD	ENST00000592014.6	c.5G>A	p.Cys2Tyr	missense_variant	Exon 1 of 5	1	NM_001077620.3	ENSP00000467661.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Alfa AF: 0.000289 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Retinitis pigmentosa 36 Pathogenic:1

Nov 01, 2006

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

not provided Uncertain:1

Aug 04, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 2 of the PRCD protein (p.Cys2Tyr). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with retinitis pigmentosa (PMID: 16938425). ClinVar contains an entry for this variant (Variation ID: 1188). Studies have shown that this missense change alters PRCD gene expression (PMID: 24992209). 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	0.88
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.56	D;D
Eigen	Uncertain	0.68
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.54	.;T
M_CAP	Uncertain	0.26	D
MetaRNN	Pathogenic	0.95	D;D
MetaSVM	Uncertain	0.041	D
PhyloP100		5.6
PrimateAI	Pathogenic	0.85	D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.90
MutPred		0.72		Gain of disorder (P = 0.0285);Gain of disorder (P = 0.0285);
MVP		0.91
MPC		0.50
ClinPred		0.97	D
GERP RS		4.8
PromoterAI		0.055	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.93
gMVP		0.19
Mutation Taster		=29/71	disease causing (ClinVar)

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: rs121918369; hg19: chr17-74536228;