rs267608682
Variant summary
Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM2PP2PP3_ModeratePP5_Very_Strong
The NM_007055.4(POLR3A):c.3013C>T(p.Arg1005Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000889 in 1,461,838 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 Likely pathogenic (★★).
Frequency
Consequence
NM_007055.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 13 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD3 exomes AF: 0.0000239 AC: 6AN: 251424Hom.: 0 AF XY: 0.0000221 AC XY: 3AN XY: 135878
GnomAD4 exome AF: 0.00000889 AC: 13AN: 1461838Hom.: 0 Cov.: 31 AF XY: 0.00000963 AC XY: 7AN XY: 727224
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Leukoencephalopathy, ataxia, hypodontia, hypomyelination syndrome Pathogenic:2Other:1
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not provided Pathogenic:1
This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 1005 of the POLR3A protein (p.Arg1005Cys). This variant is present in population databases (rs267608682, gnomAD 0.006%). This missense change has been observed in individual(s) with hypomyelinating leukodystrophy (PMID: 21855841, 22036171, 23355746). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 31149). 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 not expected to disrupt POLR3A protein function with a negative predictive value of 80%. This variant disrupts the p.Arg1005 amino acid residue in POLR3A. Other variant(s) that disrupt this residue have been observed in individuals with POLR3A-related conditions (PMID: 22451160), which suggests that this may be a clinically significant amino acid residue. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Leukodystrophy Pathogenic:1
The p.Arg1005Cys variant in POLR3A has been reported in 5 individual with hypomyelinating leukodystrophy (PMID:25339210, 34953043, 23355746, 21855841, 22036171), and has been identified in 0.009% (3/34590) of Latino/Admixed American chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs267608682). 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#: 31149) and has been interpreted as pathogenic by GeneReviews and OMIM and likely pathogenic by Invitae and DASA. Of the 5 affected individuals, 1 was a compound heterozygote that carried a reported likely pathogenic variant in trans, which increases the likelihood that the p.Arg1005Cys variant is pathogenic (VariationID: 41245; PMID: 22036171). In vitro functional studies provide some evidence that the p.Arg1005Cys variant may impact protein function (PMID: 21855841). However, these types of assays may not accurately represent biological function. Computational prediction tools and conservation analyses do not provide strong support for or against an impact to the protein. The p.Arg1005Cys variant is located in a region of POLR3A that is essential to protein folding and stability, suggesting that this variant is in a functional domain and slightly supports pathogenicity (PMID: 21855841). In summary, although additional studies are required to fully establish its clinical significance, this variant is likely pathogenic for autosomal recessive hypomyelinating leukodystrophy. ACMG/AMP Criteria applied: PM3, PS3_moderate, PM1_supporting, PM2_supporting (Richards 2015). -
Neonatal pseudo-hydrocephalic progeroid syndrome Pathogenic:1
The c.3013C>T;p.(Arg1005Cys) missense variant has been observed in affected individual(s) and ClinVar contains an entry for this variant (ClinVar ID: 31149; PMID: 23965854; 22451160; 22036171; 21855841) - PS4_moderate. The variant is located in a mutational hot spot and/or critical and well-established functional domain (RNA_pol_Rpb1_5) - PM1. The variant is present at low allele frequencies population databases (rs267608682 – gnomAD 0.0002386%; ABraOM no frequency - http://abraom.ib.usp.br/) - PM2_supporting. The p.(Arg1005Cys) was detected in trans with a pathogenic variant (PMID: 23965854; 22451160; 22036171; 21855841) - PM3. Pathogenic missense variant in this residue have been reported (ClinVar ID: 41246 - c.3014G>A;p.(Arg1005His)) - PM5. In summary, the currently available evidence indicates that the variant is likely pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at