rs756872503

Positions:

• chr19-50416608-AG-A
• chr19-50416608-AG-AGG

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 8P and 4B. PVS1 BS2

The NM_002691.4(POLD1):​c.2959delG​(p.Asp987fs) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000064 in 1,406,512 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000064 (0 hom.)
• Consequence: POLD1 NM_002691.4 frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.47

Genes affected

POLD1 (HGNC:9175): (DNA polymerase delta 1, catalytic subunit) This gene encodes the 125-kDa catalytic subunit of DNA polymerase delta. DNA polymerase delta possesses both polymerase and 3' to 5' exonuclease activity and plays a critical role in DNA replication and repair. Alternatively spliced transcript variants have been observed for this gene, and a pseudogene of this gene is located on the long arm of chromosome 6. [provided by RefSeq, Mar 2012]

ENSG00000142539 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• BS2: High AC in GnomAdExome4 at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POLD1	NM_002691.4	c.2959delG	p.Asp987fs	frameshift_variant	24/27	ENST00000440232.7	NP_002682.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POLD1	ENST00000440232.7	c.2959delG	p.Asp987fs	frameshift_variant	24/27	1	NM_002691.4	ENSP00000406046.1
ENSG00000142539	ENST00000599632.1	c.166delG	p.Asp56fs	frameshift_variant	3/10	5		ENSP00000473233.1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000640 AC: 9 AN: 1406512 Hom.: 0 Cov.: 34 AF XY: 0.00000719 AC XY: 5 AN XY: 695620

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: 0.0000374

Gnomad4 FIN exome AF: 0.0000688

Gnomad4 NFE exome AF: 0.00000276

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Colorectal cancer, susceptibility to, 10 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 27, 2022

This variant has not been reported in the literature in individuals affected with POLD1-related conditions. 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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 935838). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change creates a premature translational stop signal (p.Asp987Thrfs*58) in the POLD1 gene. Missense variants that disrupt the 3'-5' exonuclease (proof-reading) activity of the POLD1 protein are associated with PPAP (polymerase proofreading–associated polyposis) (PMID: 23263490, 23447401). However, loss-of-function variants that result in an absent or severely disrupted POLD1 protein, and missense variants outside the exonuclease domain, are unlikely to be associated with PPAP. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		1.0		Position offset: 3
DS_AL_spliceai		1.0		Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs756872503; hg19: chr19-50919865;