ClinVar

Description

The c.1672C>T variant identified in WFS1 has been reported in homozygous as well as compound heterozygous states in at least 20 individuals with late-onset Wolfram syndrome [PMID: 17568405, 21446023, 22226368, 24890733, 30014265, 30957632, 33763535], and it has been deposited in ClinVar [ClinVarID:198835]. The c.1672C>T is observed in 218 alleles (~0.05% minor allele frequency (MAF) with 1 homozygote) in population databases (gnomAD v2.1.1 and v3.1.2), with having >1% MAF in individuals of Ashkenazi Jewish ancestry suggesting it might be a founder variant in that population. Of note, those population databases include individuals with late onset disorders like diabetes mellitus. The c.1672C>T variant is located in exon 8 of this 8-exon gene and predicted to replace an evolutionarily conserved arginine aminoacid with cysteine at position 558 (p.(Arg558Cys)) in the cytoplasmic linker region connecting transmembrane domains VI and VII of the encoded protein [see Figure 1 in PMID:20301750]. In silico predictions are moderately in favor of damaging effect for p.(Arg558Cys) [CADD v1.6 = 25.5,REVEL = 0.816]; however, there are no functional studies to support or refute these predictions. Another variant affecting the same amino acid residue(c.1673G>A:p.(Arg558His)) has also been reported in the literature [PMID: 12754709, 21446023, 24890733, 31567480] and ClinVar [ClinVar ID: 427051] in individuals with late-onset Wolfram syndrome. Based on available evidence the c.1672C>T p.(Arg558Cys) variant identified in WFS1 is classified as Pathogenic for autosomal recessive late-onset Wolfram syndrome.