chr10-77991125-C-A

Variant names:

• chr10-77991125-C-A
• rs267608674
• NM_007055.4:c.2830G>T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_007055.4(POLR3A):​c.2830G>T​(p.Glu944*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000411 in 1,461,530 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 Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: POLR3A NM_007055.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1 O:1
• Conservation: PhyloP100: 5.80

Genes affected

POLR3A (HGNC:30074): (RNA polymerase III subunit A) The protein encoded by this gene is the catalytic component of RNA polymerase III, which synthesizes small RNAs. The encoded protein also acts as a sensor to detect foreign DNA and trigger an innate immune response. [provided by RefSeq, Aug 2011]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 10-77991125-C-A is Pathogenic according to our data. Variant chr10-77991125-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 41245.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr10-77991125-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POLR3A	NM_007055.4	c.2830G>T	p.Glu944*	stop_gained	Exon 21 of 31	ENST00000372371.8	NP_008986.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POLR3A	ENST00000372371.8	c.2830G>T	p.Glu944*	stop_gained	Exon 21 of 31	1	NM_007055.4	ENSP00000361446.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251158 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135734

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: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1461530 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 727090

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: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000307 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Leukodystrophy Pathogenic:1

Jan 24, 2023

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

The p.Glu944Ter variant in POLR3A has been reported in 1 individual with hypomyelinating leukodystrophy (PMID: 21855841), and has been identified in 0.001% (1/113478) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs267608674). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. This variant has also been reported in ClinVar (Variation ID#: 41245) and has been interpreted as pathogenic by GeneReviews. In vitro functional studies provide some evidence that the p.Glu944Ter variant may impact protein function (PMID: 21855841). However, these types of assays may not accurately represent biological function. This nonsense variant leads to a premature termination codon at position 944, which is predicted to lead to a truncated or absent protein. Loss of function of the POLR3A gene is an established disease mechanism in autosomal recessive hypomyelinating leukodystrophy. In summary, while there is some suspicion for a pathogenic role, the clinical significance of this variant is uncertain. ACMG/AMP Criteria applied: PVS1, PM2_supporting, PS3_moderate (Richards 2015). -

Leukoencephalopathy, ataxia, hypodontia, hypomyelination syndrome Other:1

-

GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.65
CADD	Pathogenic	43
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
Vest4		0.90
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs267608674; hg19: chr10-79750883;