19-50409154-C-T

Variant names:

• chr19-50409154-C-T
• rs878854529
• NM_002691.4:c.1925C>T

Variant summary

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

The NM_002691.4(POLD1):​c.1925C>T​(p.Thr642Ile) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. T642S) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: POLD1 NM_002691.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.99
• Publications: 0 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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POLD1	NM_002691.4	c.1925C>T	p.Thr642Ile	missense_variant	Exon 16 of 27	ENST00000440232.7	NP_002682.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POLD1	ENST00000440232.7	c.1925C>T	p.Thr642Ile	missense_variant	Exon 16 of 27	1	NM_002691.4	ENSP00000406046.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

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

Sep 30, 2023

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: 1782755). 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 threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 642 of the POLD1 protein (p.Thr642Ile). -

Hereditary cancer-predisposing syndrome Uncertain:1

Feb 14, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T642I variant (also known as c.1925C>T), located in coding exon 15 of the POLD1 gene, results from a C to T substitution at nucleotide position 1925. The threonine at codon 642 is replaced by isoleucine, an amino acid with similar 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	Pathogenic	0.88
BayesDel_addAF	Benign	-0.082	T
BayesDel_noAF	Benign	-0.36
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.28	T;.;.;T
Eigen	Benign	0.11
Eigen_PC	Benign	0.18
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	.;.;D;D
M_CAP	Benign	0.025	D
MetaRNN	Uncertain	0.58	D;D;D;D
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.9	L;.;.;L
PhyloP100		7.0
PrimateAI	Uncertain	0.75	T
PROVEAN	Uncertain	-3.0	D;.;.;.
REVEL	Benign	0.14
Sift	Uncertain	0.028	D;.;.;.
Sift4G	Benign	0.23	T;T;T;T
Polyphen		0.45	B;.;.;B
Vest4		0.69
MutPred		0.52		Loss of phosphorylation at T642 (P = 0.039);.;.;Loss of phosphorylation at T642 (P = 0.039);
MVP		0.59
MPC		1.5
ClinPred		0.95	D
GERP RS		3.3
Varity_R		0.26
gMVP		0.64
Mutation Taster		=40/60	disease causing

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: rs878854529; hg19: chr19-50912411;