NM_002691.4:c.658G>T

Variant names:

• chr19-50402273-G-T
• rs749052483
• NM_002691.4:c.658G>T

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_Moderate BP6

The NM_002691.4(POLD1):​c.658G>T​(p.Val220Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000413 in 1,453,782 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V220M) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: POLD1 NM_002691.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: -0.715
• Publications: 2 publications found

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 Gene-Disease associations (from GenCC):

• POLD1-related polyposis and colorectal cancer syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• colorectal cancer, susceptibility to, 10

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Genomics England PanelApp
• mandibular hypoplasia-deafness-progeroid syndrome

  Inheritance: AD, AR Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia, Genomics England PanelApp, Ambry Genetics, Orphanet, G2P
• Polymerase proofreading-related adenomatous polyposis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• immunodeficiency 120

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics
• non-severe combined immunodeficiency due to polymerase delta deficiency

  Inheritance: AR Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.081507415).
• BP6: Variant 19-50402273-G-T is Benign according to our data. Variant chr19-50402273-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 851437.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POLD1	NM_002691.4	c.658G>T	p.Val220Leu	missense_variant	Exon 6 of 27	ENST00000440232.7	NP_002682.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POLD1	ENST00000440232.7	c.658G>T	p.Val220Leu	missense_variant	Exon 6 of 27	1	NM_002691.4	ENSP00000406046.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.0000165 AC: 4 AN: 242988 AF XY: 0.0000152

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000889

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000916

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000413 AC: 6 AN: 1453782 Hom.: 0 Cov.: 34 AF XY: 0.00000277 AC XY: 2 AN XY: 722216

African (AFR) AF: 0.00 AC: 0 AN: 33270

American (AMR) AF: 0.0000682 AC: 3 AN: 43986

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25654

East Asian (EAS) AF: 0.00 AC: 0 AN: 39546

South Asian (SAS) AF: 0.00 AC: 0 AN: 85362

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53034

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5742

European-Non Finnish (NFE) AF: 0.00000271 AC: 3 AN: 1107210

Other (OTH) AF: 0.00 AC: 0 AN: 59978

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000830 AC: 1

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Colorectal cancer, susceptibility to, 10 Uncertain:1

Oct 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces valine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 220 of the POLD1 protein (p.Val220Leu). This variant is present in population databases (rs749052483, gnomAD 0.009%). This variant has not been reported in the literature in individuals affected with POLD1-related conditions. ClinVar contains an entry for this variant (Variation ID: 851437). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt POLD1 protein function with a negative predictive value of 80%. 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. -

Hereditary cancer-predisposing syndrome Benign:1

Jan 17, 2025

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Benign	-0.48	T
BayesDel_noAF	Benign	-0.73
CADD	Benign	1.9
DANN	Benign	0.93
DEOGEN2	Benign	0.17	T;.;.;T
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.29	N
LIST_S2	Uncertain	0.88	.;.;D;D
M_CAP	Benign	0.0093	T
MetaRNN	Benign	0.082	T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.20	N;.;.;N
PhyloP100		-0.71
PrimateAI	Benign	0.41	T
PROVEAN	Benign	-1.2	N;.;.;.
REVEL	Benign	0.035
Sift	Benign	0.24	T;.;.;.
Sift4G	Benign	0.23	T;T;T;T
Polyphen		0.0030	B;.;.;B
Vest4		0.17
MutPred		0.61		Loss of MoRF binding (P = 0.085);Loss of MoRF binding (P = 0.085);Loss of MoRF binding (P = 0.085);Loss of MoRF binding (P = 0.085);
MVP		0.15
MPC		0.19
ClinPred		0.052	T
GERP RS		-4.8
Varity_R		0.11
gMVP		0.50
Mutation Taster		=89/11	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs749052483; hg19: chr19-50905530;