chr9-97684929-C-CT

Position:

• chr9-97684929-C-CT

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000380.4(XPA):​c.666_667insA​(p.Val223SerfsTer23) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,620 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: XPA NM_000380.4 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 1.62

Genes affected

XPA (HGNC:12814): (XPA, DNA damage recognition and repair factor) This gene encodes a zinc finger protein plays a central role in nucleotide excision repair (NER), a specialized type of DNA repair. NER is responsible for repair of UV radiation-induced photoproducts and DNA adducts induced by chemical carcinogens and chemotherapeutic drugs. The encoded protein interacts with DNA and several NER proteins, acting as a scaffold to assemble the NER incision complex at sites of DNA damage. Mutations in this gene cause Xeroderma pigmentosum complementation group A (XP-A), an autosomal recessive skin disorder featuring hypersensitivity to sunlight and increased risk for skin cancer. [provided by RefSeq, Aug 2017]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.19 CDS is truncated, and there are 1 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 9-97684929-C-CT is Pathogenic according to our data. Variant chr9-97684929-C-CT is described in ClinVar as [Likely_pathogenic]. Clinvar id is 553445.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
XPA	NM_000380.4	c.666_667insA	p.Val223SerfsTer23	frameshift_variant	5/6	ENST00000375128.5	NP_000371.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
XPA	ENST00000375128.5	c.666_667insA	p.Val223SerfsTer23	frameshift_variant	5/6	1	NM_000380.4	ENSP00000364270	P1
XPA	ENST00000462523.5	c.666_667insA	p.Val223SerfsTer11	frameshift_variant, NMD_transcript_variant	5/7	5		ENSP00000433006
XPA	ENST00000496104.1			downstream_gene_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460620 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 726672

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Xeroderma pigmentosum Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jun 08, 2018

Variant summary: XPA c.666dupA (p.Val223SerfsX23) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant was absent in 245964 control chromosomes (gnomAD). The variant, c.666dupA, has been reported in the literature in individuals affected with Xeroderma Pigmentosum (Cleaver_1999). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Xeroderma pigmentosum group A Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Counsyl

Aug 25, 2017

- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 17, 2023

This sequence change creates a premature translational stop signal (p.Val223Serfs*23) in the XPA gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 51 amino acid(s) of the XPA protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with mild clinical features of xeroderma pigmentosum (PMID: 8541864). ClinVar contains an entry for this variant (Variation ID: 553445). This variant disrupts a region of the XPA protein in which other variant(s) (p.Arg228*) have been determined to be pathogenic (PMID: 8105686, 26743599, 29208038). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs1554701103; hg19: chr9-100447211;