rs76131127

Positions:

• chr19-50402468-C-G
• chr19-50402468-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_002691.4(POLD1):​c.773C>G​(p.Thr258Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict 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. T258M) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: POLD1 NM_002691.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.737

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 Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.14314201).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POLD1	NM_002691.4	c.773C>G	p.Thr258Arg	missense_variant	7/27	ENST00000440232.7	NP_002682.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POLD1	ENST00000440232.7	c.773C>G	p.Thr258Arg	missense_variant	7/27	1	NM_002691.4	ENSP00000406046	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Colorectal cancer, susceptibility to, 10 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 07, 2020

This sequence change replaces threonine with arginine at codon 258 of the POLD1 protein (p.Thr258Arg). The threonine residue is weakly conserved and there is a moderate physicochemical difference between threonine and arginine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with POLD1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.080
BayesDel_addAF	Benign	-0.26	T
BayesDel_noAF	Benign	-0.62
CADD	Benign	18
DANN	Benign	0.94
DEOGEN2	Benign	0.38	T;.;.;T
Eigen	Benign	-0.73
Eigen_PC	Benign	-0.69
FATHMM_MKL	Benign	0.078	N
LIST_S2	Uncertain	0.91	.;.;D;D
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.14	T;T;T;T
MetaSVM	Benign	-0.96	T
MutationAssessor	Benign	1.3	L;.;.;L
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.39	T
PROVEAN	Uncertain	-3.4	D;.;.;.
REVEL	Benign	0.061
Sift	Benign	0.22	T;.;.;.
Sift4G	Benign	0.37	T;T;T;T
Polyphen		0.0010	B;.;.;B
Vest4		0.20
MutPred		0.47		Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);
MVP		0.47
MPC		0.22
ClinPred		0.098	T
GERP RS		3.0
Varity_R		0.24
gMVP		0.64

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		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: rs76131127; hg19: chr19-50905725;