rs775317882

chr19-50414853-C-Achr19-50414853-C-Gchr19-50414853-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_002691.4(POLD1):c.2427C>A(p.Tyr809Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000691 in 1,446,298 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. Y809Y) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: POLD1 NM_002691.4 stop_gained
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: -1.38

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
POLD1	NM_002691.4	c.2427C>A	p.Tyr809Ter	stop_gained	20/27	ENST00000440232.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POLD1	ENST00000440232.7	c.2427C>A	p.Tyr809Ter	stop_gained	20/27	1	NM_002691.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.91e-7 AC: 1 AN: 1446298 Hom.: 0 Cov.: 31 AF XY: 0.00000139 AC XY: 1 AN XY: 718388

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: 9.07e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Colorectal cancer, susceptibility to, 10 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Apr 18, 2021

Missense variants that disrupt the 3'-5' exonuclease (proof-reading) activity of the POLD1/POLE protein, while not abolishing its polymerase enzyme activity, are associated with an increased risk for colonic adenomatous polyps and colon cancer (PMID: 23263490, 23447401). Loss-of-function truncating variants, which result in an absent or severely disrupted POLD1/POLE protein, are therefore unlikely to be associated with disease. Without further clinical and genetic evidence, however, this variant has been classified as a Variant of Uncertain Significance. This variant has not been reported in the literature in individuals with POLD1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Tyr809*) in the POLD1 gene. It is expected to result in an absent or disrupted protein product. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 30, 2018

The p.Y809* variant (also known as c.2427C>A), located in coding exon 19 of the POLD1 gene, results from a C to A substitution at nucleotide position 2427. This changes the amino acid from a tyrosine to a stop codon within coding exon 19. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. However, loss of function via haploinsufficiency in POLD1 has not been clearly established as a mechanism of disease. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.36
Cadd	Benign	22
Dann	Benign	0.95
Eigen	Benign	-0.82
Eigen_PC	Benign	-1.3
FATHMM_MKL	Benign	0.062	N
MutationTaster	Benign	1.0	A
Vest4		0.90
GERP RS		-9.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs775317882; hg19: chr19-50918110;