chr19-50409535-G-A

Variant names:

• chr19-50409535-G-A
• rs753870000
• NM_002691.4:c.2023G>A

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_002691.4(POLD1):​c.2023G>A​(p.Ala675Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,180 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A675S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: POLD1 NM_002691.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 3.32
• Publications: 3 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: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.25240627).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POLD1	NM_002691.4	c.2023G>A	p.Ala675Thr	missense_variant	Exon 17 of 27	ENST00000440232.7	NP_002682.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POLD1	ENST00000440232.7	c.2023G>A	p.Ala675Thr	missense_variant	Exon 17 of 27	1	NM_002691.4	ENSP00000406046.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461180 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726938

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52738

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112004

Other (OTH) AF: 0.00 AC: 0 AN: 60390

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

POLD1-related disorder Uncertain:1

Jul 17, 2024

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The POLD1 c.2023G>A variant is predicted to result in the amino acid substitution p.Ala675Thr. To our knowledge, this variant has not been reported in the literature or in a large population database, indicating this variant is rare. This variant is interpreted as a variant of uncertain significance in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/469233/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Colorectal cancer, susceptibility to, 10 Uncertain:1

Oct 13, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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: 469233). This variant has not been reported in the literature in individuals affected with POLD1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 675 of the POLD1 protein (p.Ala675Thr). -

Hereditary cancer-predisposing syndrome Uncertain:1

Apr 18, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.2023G>A (p.A675T) alteration is located in exon 17 (coding exon 16) of the POLD1 gene. This alteration results from a G to A substitution at nucleotide position 2023, causing the alanine (A) at amino acid position 675 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.46
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.28	T;.;.;T
Eigen	Benign	0.12
Eigen_PC	Benign	0.21
FATHMM_MKL	Benign	0.74	D
LIST_S2	Pathogenic	0.98	.;.;D;D
M_CAP	Benign	0.018	T
MetaRNN	Benign	0.25	T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Uncertain	2.9	M;.;.;M
PhyloP100		3.3
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-0.67	N;.;.;.
REVEL	Benign	0.072
Sift	Uncertain	0.029	D;.;.;.
Sift4G	Uncertain	0.037	D;D;D;D
Polyphen		0.11	B;.;.;B
Vest4		0.30
MutPred		0.43		Gain of phosphorylation at A675 (P = 0.0736);.;.;Gain of phosphorylation at A675 (P = 0.0736);
MVP		0.50
MPC		0.97
ClinPred		0.86	D
GERP RS		4.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Varity_R		0.065
gMVP		0.37
Mutation Taster		=74/26	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs753870000; hg19: chr19-50912792;