X-24699423-A-G

Position:

chrX-24699423-A-G

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PVS1_ModerateBS1_SupportingBS2

The NM_001330360.2(POLA1):c.44-2A>G variant causes a splice acceptor change. The variant allele was found at a frequency of 0.00000875 in 1,142,712 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 5 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000036 ( 0 hom., 1 hem., cov: 22)

Exomes 𝑓: 0.0000058 ( 0 hom. 4 hem. )

Consequence

POLA1
NM_001330360.2 splice_acceptor

Scores

Splicing: ADA: 0.9970

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 3.80

Variant links:

Genes affected

POLA1 (HGNC:9173): (DNA polymerase alpha 1, catalytic subunit) This gene encodes the catalytic subunit of DNA polymerase, which together with a regulatory and two primase subunits, forms the DNA polymerase alpha complex. The catalytic subunit plays an essential role in the initiation of DNA replication. [provided by RefSeq, Mar 2010]

POLA1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.028137054 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7.7, offset of 9, new splice context is: tcttttttcggctctgtcAGatt. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0000359 (4/111339) while in subpopulation AFR AF= 0.000131 (4/30607). AF 95% confidence interval is 0.0000444. There are 0 homozygotes in gnomad4. There are 1 alleles in male gnomad4 subpopulation. Median coverage is 22. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

BS2

High Hemizygotes in GnomAdExome4 at 4 XL gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POLA1	NM_001330360.2 linkuse as main transcript	c.44-2A>G		splice_acceptor_variant		ENST00000379068.8	NP_001317289.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POLA1	ENST00000379068.8 linkuse as main transcript	c.44-2A>G		splice_acceptor_variant		5	NM_001330360.2	ENSP00000368358	A1

Frequencies

GnomAD3 genomes

AF:

0.0000359

AC:

AN:

111339

Hom.:

Cov.:

AF XY:

0.0000298

AC XY:

AN XY:

33555

show subpopulations

Gnomad AFR

AF:

0.000131

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000582

AC:

AN:

1031373

Hom.:

Cov.:

AF XY:

0.0000125

AC XY:

AN XY:

321189

show subpopulations

Gnomad4 AFR exome

AF:

0.000250

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:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000359

AC:

AN:

111339

Hom.:

Cov.:

AF XY:

0.0000298

AC XY:

AN XY:

33555

show subpopulations

Gnomad4 AFR

AF:

0.000131

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000529

ExAC

AF:

0.0000249

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 06, 2022

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 1397392). This variant has not been reported in the literature in individuals affected with POLA1-related conditions. 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 sequence change affects an acceptor splice site in intron 1 of the POLA1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), however the current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in POLA1 cause disease. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Benign

-0.44

BayesDel_noAF

Benign

-0.87

CADD

Pathogenic

DANN

Benign

0.44

FATHMM_MKL

Benign

0.73

MutationTaster

Benign

1.0

N;N

GERP RS

1.4

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Benign

0.47

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.98

Position offset: 11

DS_AL_spliceai

1.0

Position offset: 2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over