chr19-50406479-A-G

Position:

• chr19-50406479-A-G

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 3P and 4B. PM5 PP3 BS2

The NM_002691.4(POLD1):​c.1456A>G​(p.Lys486Glu) variant causes a missense change. The variant allele was found at a frequency of 0.00000416 in 1,443,722 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. K486N) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000042 (0 hom.)
• Consequence: POLD1 NM_002691.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 6.69

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 Likely_benign. Variant got -1 ACMG points.

• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-50406481-G-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.84
• BS2: High AC in GnomAdExome4 at 6 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
POLD1	NM_002691.4	c.1456A>G	p.Lys486Glu	missense_variant	12/27	ENST00000440232.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POLD1	ENST00000440232.7	c.1456A>G	p.Lys486Glu	missense_variant	12/27	1	NM_002691.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000454 AC: 1 AN: 220126 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 118390

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000103

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000416 AC: 6 AN: 1443722 Hom.: 0 Cov.: 36 AF XY: 0.00000140 AC XY: 1 AN XY: 716572

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000544

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Colorectal cancer, susceptibility to, 10 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Sep 29, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Dec 17, 2023	This sequence change replaces lysine, which is basic and polar, with glutamic acid, which is acidic and polar, at codon 486 of the POLD1 protein (p.Lys486Glu). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. 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: 407945). 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 expected to disrupt POLD1 protein function with a positive predictive value of 80%. This variant disrupts the p.Lys486 amino acid residue in POLD1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 34954152). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 06, 2023

The p.K486E variant (also known as c.1456A>G), located in coding exon 11 of the POLD1 gene, results from an A to G substitution at nucleotide position 1456. The lysine at codon 486 is replaced by glutamic acid, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. 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	1.0
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.040
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.89	D;.;.;D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	1.0	.;.;D;D
M_CAP	Pathogenic	0.45	D
MetaRNN	Pathogenic	0.84	D;D;D;D
MetaSVM	Uncertain	-0.067	T
MutationAssessor	Pathogenic	4.6	H;.;.;H
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Uncertain	-3.9	D;.;.;.
REVEL	Uncertain	0.49
Sift	Pathogenic	0.0	D;.;.;.
Sift4G	Pathogenic	0.0010	D;D;D;D
Polyphen		1.0	D;.;.;D
Vest4		0.69
MutPred		0.65		Loss of ubiquitination at K486 (P = 0.0148);Loss of ubiquitination at K486 (P = 0.0148);Loss of ubiquitination at K486 (P = 0.0148);Loss of ubiquitination at K486 (P = 0.0148);
MVP		0.82
MPC		1.5
ClinPred		1.0	D
GERP RS		4.6
Varity_R		0.96
gMVP		0.95

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs527486070; hg19: chr19-50909736;