19-50416608-AG-AGG

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PP3_Moderate

The NM_002691.4(POLD1):c.2959dupG(p.Asp987fs) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000513 in 1,558,678 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. D987D) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 34)

Exomes 𝑓: 0.0000036 ( 0 hom. )

Consequence

POLD1
NM_002691.4 frameshift

Scores

Not classified

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 8.47

Publications

0 publications found

Variant links:

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

POLD1 links:

ENSG00000142539 (HGNC:):

ENSG00000142539 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002691.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
POLD1	NM_002691.4	MANE Select	c.2959dupG	p.Asp987fs	frameshift	Exon 24 of 27	NP_002682.2
POLD1	NM_001308632.1		c.3037dupG	p.Asp1013fs	frameshift	Exon 23 of 26	NP_001295561.1
POLD1	NM_001256849.1		c.2959dupG	p.Asp987fs	frameshift	Exon 24 of 27	NP_001243778.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
POLD1	ENST00000440232.7	TSL:1 MANE Select	c.2959dupG	p.Asp987fs	frameshift	Exon 24 of 27	ENSP00000406046.1
POLD1	ENST00000595904.6	TSL:1	c.3037dupG	p.Asp1013fs	frameshift	Exon 24 of 27	ENSP00000472445.1
POLD1	ENST00000599857.7	TSL:1	c.2959dupG	p.Asp987fs	frameshift	Exon 24 of 27	ENSP00000473052.1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152126

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000185

AC:

AN:

162082

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.000117

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000893

Gnomad NFE exome

AF:

0.0000149

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000355

AC:

AN:

1406552

Hom.:

Cov.:

AF XY:

0.00000144

AC XY:

AN XY:

695646

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

32142

American (AMR)

AF:

0.00

AC:

AN:

37348

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25236

East Asian (EAS)

AF:

0.00

AC:

AN:

36610

South Asian (SAS)

AF:

0.00

AC:

AN:

80280

European-Finnish (FIN)

AF:

0.0000459

AC:

AN:

43616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5342

European-Non Finnish (NFE)

AF:

0.00000184

AC:

AN:

1087498

Other (OTH)

AF:

0.0000171

AC:

AN:

58480

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0509366), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.395

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152126

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74308

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41434

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67992

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000540

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Colorectal cancer, susceptibility to, 10;C3715192:Mandibular hypoplasia-deafness-progeroid syndrome

Uncertain:1

Oct 25, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not provided

Uncertain:1

Sep 16, 2023

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is not an established mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 23447401, 23263490)

Colorectal cancer, susceptibility to, 10

Uncertain:1

Aug 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Asp987Glyfs*41) in the POLD1 gene. Missense variants that disrupt the 3'-5' exonuclease (proof-reading) activity of the POLD1 protein are associated with PPAP (polymerase proofreading‚Äìassociated polyposis) (PMID: 23263490, 23447401). However, loss-of-function variants that result in an absent or severely disrupted POLD1 protein, and missense variants outside the exonuclease domain, are unlikely to be associated with PPAP. 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: 537052). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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

Dec 20, 2024

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.2959dupG variant, located in coding exon 23 of the POLD1 gene, results from a duplication of G at nucleotide position 2959, causing a translational frameshift with a predicted alternate stop codon (p.D987Gfs*41). This alteration is expected to result in protein truncation or nonsense-mediated mRNA decay. However, loss of function of POLD1 has not been established as a mechanism of disease. Based on the available evidence, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

PhyloP100

8.5

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_AG_spliceai

1.0

Position offset: 1

DS_AL_spliceai

1.0

Position offset: 2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over