Submissions for variant NM_002693.3(POLG):c.2555G>A (p.Arg852His)

dbSNP: rs1567187093

Total submissions: 2

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine	RCV000758450	SCV000887160	likely pathogenic	Progressive sclerosing poliodystrophy	2018-10-01	criteria provided, single submitter	clinical testing	The NM_002693.2:c.2555G>A (NP_002684.1:p.Arg852His) [GRCH38: NC_000015.10:g.89321779C>T] variant in POLG gene is interpretated to be a Likely Pathogenic based on ACMG guidelines (PMID: 25741868). This variant meets the following evidence codes reported in the ACMG-guideline. PM1:This variant is in mutational hot spot or a well-studied functional domain without benign variation. PM2:This variant is absent in key population databases. PM3:Detected in trans with a pathogenic variant for Mitochondrial DNA depletion syndrome 4A (Alpers type) which is a recessive disorder. PP1:This variant is co-segregated with Mitochondrial DNA depletion syndrome 4A (Alpers type) in multiple affected family members. PP2:This is a missense variant in POLG with a low rate of benign and high rate of pathogenic missense variations. PP3:Computational evidence/predictors indicate the variant has deleterious effect on POLG structure, function, or protein-protein interaction. PP4:Patient's phenotype or family history is highly specific for POLG. Based on the evidence criteria codes applied, the variant is suggested to be Likely Pathogenic.
Labcorp Genetics (formerly Invitae), Labcorp	RCV000758450	SCV004296590	likely pathogenic	Progressive sclerosing poliodystrophy	2024-03-27	criteria provided, single submitter	clinical testing	This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 852 of the POLG protein (p.Arg852His). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with autosomal recessive Alpers-Huttenlocher syndrome (PMID: 21880868). ClinVar contains an entry for this variant (Variation ID: 619418). 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 POLG protein function with a positive predictive value of 95%. This variant disrupts the p.Arg852 amino acid residue in POLG. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 16545482, 18546365, 21880868, 22000311). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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.