8-54626476-CTT-C

Variant names:

• chr8-54626476-CTT-C
• rs1554519635
• NM_006269.2:c.2596_2597delTT

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_006269.2(RP1):​c.2596_2597delTT​(p.Leu866LysfsTer7) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,670 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: RP1 NM_006269.2 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 1.27

Genes affected

RP1 (HGNC:10263): (RP1 axonemal microtubule associated) This gene encodes a member of the doublecortin family. The protein encoded by this gene contains two doublecortin domains, which bind microtubules and regulate microtubule polymerization. The encoded protein is a photoreceptor microtubule-associated protein and is required for correct stacking of outer segment disc. This protein and the RP1L1 protein, another retinal-specific protein, play essential and synergistic roles in affecting photosensitivity and outer segment morphogenesis of rod photoreceptors. Because of its response to in vivo retinal oxygen levels, this protein was initially named ORP1 (oxygen-regulated protein-1). This protein was subsequently designated RP1 (retinitis pigmentosa 1) when it was found that mutations in this gene cause autosomal dominant retinitis pigmentosa. Mutations in this gene also cause autosomal recessive retinitis pigmentosa. Transcript variants resulted from an alternative promoter and alternative splicings have been found, which overlap the current reference sequence and has several exons upstream and downstream of the current reference sequence. However, the biological validity and full-length nature of some variants cannot be determined at this time.[provided by RefSeq, Sep 2010]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 67 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 8-54626476-CTT-C is Pathogenic according to our data. Variant chr8-54626476-CTT-C is described in ClinVar as [Pathogenic]. Clinvar id is 437954.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr8-54626476-CTT-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RP1	NM_006269.2	c.2596_2597delTT	p.Leu866LysfsTer7	frameshift_variant	Exon 4 of 4	ENST00000220676.2	NP_006260.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RP1	ENST00000220676.2	c.2596_2597delTT	p.Leu866LysfsTer7	frameshift_variant	Exon 4 of 4	1	NM_006269.2	ENSP00000220676.1
RP1	ENST00000637698.1	c.787+4190_787+4191delTT		intron_variant	Intron 3 of 28	5		ENSP00000490104.1
RP1	ENST00000636932.1	c.787+4190_787+4191delTT		intron_variant	Intron 3 of 22	5		ENSP00000489857.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461670 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 727120

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Jul 09, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Leu866Lysfs*7) in the RP1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 1291 amino acid(s) of the RP1 protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individuals with autosomal dominant retinitis pigmentosa (PMID: 28041643, 30731082; Invitae). ClinVar contains an entry for this variant (Variation ID: 437954). This variant disrupts the C-terminus of the RP1 protein. Many variants that disrupt this region have been reported in individuals with either autosomal dominant or autosomal recessive retinitis pigmentosa (PMID: 11527933, 19933189, 29425069, 30027431, 33681214). Therefore, variants that disrupt this region are expected to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Retinitis pigmentosa Pathogenic:1

Jan 01, 2015

NIHR Bioresource Rare Diseases, University of Cambridge

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Computational scores

Source: dbNSFP v4.3

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: rs1554519635; hg19: chr8-55539036;