19-50399401-G-T

Position:

• chr19-50399401-G-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4 BS2

The NM_002691.4(POLD1):​c.233G>T​(p.Arg78Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000616 in 1,461,740 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. R78R) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000062 (0 hom.)
• Consequence: POLD1 NM_002691.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.42

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]

POLD1 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.38863617).
• 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.233G>T	p.Arg78Leu	missense_variant	3/27	ENST00000440232.7	NP_002682.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POLD1	ENST00000440232.7	c.233G>T	p.Arg78Leu	missense_variant	3/27	1	NM_002691.4	ENSP00000406046.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251372 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135872

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000616 AC: 9 AN: 1461740 Hom.: 0 Cov.: 31 AF XY: 0.00000688 AC XY: 5 AN XY: 727184

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000720

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ExAC AF: 0.0000165 AC: 2

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

Labcorp Genetics (formerly Invitae), Labcorp

May 19, 2023

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt POLD1 protein function. ClinVar contains an entry for this variant (Variation ID: 639609). This variant has not been reported in the literature in individuals affected with POLD1-related conditions. This variant is present in population databases (rs750825686, gnomAD 0.006%). This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 78 of the POLD1 protein (p.Arg78Leu). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 13, 2024

The p.R78L variant (also known as c.233G>T), located in coding exon 2 of the POLD1 gene, results from a G to T substitution at nucleotide position 233. The arginine at codon 78 is replaced by leucine, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. 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
AlphaMissense	Benign	0.15
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.40
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.61	D;.;.;.;D;.
Eigen	Benign	0.042
Eigen_PC	Benign	0.044
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.86	.;.;D;D;D;D
M_CAP	Benign	0.033	D
MetaRNN	Benign	0.39	T;T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.55	N;.;.;.;N;.
PrimateAI	Uncertain	0.56	T
PROVEAN	Uncertain	-3.6	D;.;.;.;.;.
REVEL	Benign	0.095
Sift	Benign	0.044	D;.;.;.;.;.
Sift4G	Benign	0.12	T;T;D;T;T;D
Polyphen		0.77	P;.;.;.;P;.
Vest4		0.62
MutPred		0.45		Loss of solvent accessibility (P = 0.0544);Loss of solvent accessibility (P = 0.0544);Loss of solvent accessibility (P = 0.0544);Loss of solvent accessibility (P = 0.0544);Loss of solvent accessibility (P = 0.0544);Loss of solvent accessibility (P = 0.0544);
MVP		0.58
MPC		0.55
ClinPred		0.78	D
GERP RS		3.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.37
gMVP		0.45

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: rs750825686; hg19: chr19-50902658;