10-47348577-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_002900.3(RBP3):c.93G>A(p.Met31Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000342 in 1,460,956 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: RBP3 NM_002900.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.43

Genes affected

RBP3 (HGNC:9921): (retinol binding protein 3) Interphotoreceptor retinol-binding protein is a large glycoprotein known to bind retinoids and found primarily in the interphotoreceptor matrix of the retina between the retinal pigment epithelium and the photoreceptor cells. It is thought to transport retinoids between the retinal pigment epithelium and the photoreceptors, a critical role in the visual process.The human IRBP gene is approximately 9.5 kbp in length and consists of four exons separated by three introns. The introns are 1.6-1.9 kbp long. The gene is transcribed by photoreceptor and retinoblastoma cells into an approximately 4.3-kilobase mRNA that is translated and processed into a glycosylated protein of 135,000 Da. The amino acid sequence of human IRBP can be divided into four contiguous homology domains with 33-38% identity, suggesting a series of gene duplication events. In the gene, the boundaries of these domains are not defined by exon-intron junctions, as might have been expected. The first three homology domains and part of the fourth are all encoded by the first large exon, which is 3,180 base pairs long. The remainder of the fourth domain is encoded in the last three exons, which are 191, 143, and approximately 740 base pairs long, respectively. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RBP3	NM_002900.3	c.93G>A	p.Met31Ile	missense_variant	1/4	ENST00000584701.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RBP3	ENST00000584701.2	c.93G>A	p.Met31Ile	missense_variant	1/4	1	NM_002900.3	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 250788 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135650

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000116

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1460956 Hom.: 0 Cov.: 32 AF XY: 0.00000550 AC XY: 4 AN XY: 726776

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000112

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 30, 2021

This sequence change replaces methionine with isoleucine at codon 31 of the RBP3 protein (p.Met31Ile). The methionine residue is highly conserved and there is a small physicochemical difference between methionine and isoleucine. This variant is present in population databases (rs782523591, ExAC 0.009%). This variant has not been reported in the literature in individuals affected with RBP3-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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	0.71
BayesDel_noAF	Uncertain	0.070
Cadd	Benign	22
Dann	Uncertain	0.99
DEOGEN2	Benign	0.22	T
LIST_S2	Benign	0.86	D
MetaRNN	Uncertain	0.49	T
Sift4G	Uncertain	0.010	D
Vest4		0.65
gMVP		0.96

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: rs782523591; hg19: chr10-48390785;