ClinVar

Description

Variant summary: The c.c.3557-6C>T variant involves the alteration of a non-conserved nucleotide resulting in an intronic change. This variant is located at a position that is not widely known to affect splicing, 4/5 splicing prediction tools predict no significant effect on splicing, and Mutation Taster predicts the variant to be a polymorphism. This variant was found in 324/122184 control chromosomes, predominantly observed in the European (Non-Finnish) subpopulation at a frequency of 0.0037672 (250/66362). This subpopulation frequency is lower than the estimated maximal expected allele frequency of a pathogenic ATP7B variant (0.0054006), but is high enough to suggest that variant could possibly be a benign polymorphism. Additionally, the variant is regarded as a benign variant in literature (Thomas _1995; Mukherjee_2014) and in at least one database (University of Alberta WD database); however no definite evidence was provided to independently evaluate. There was an internal finding that two variants (c.1922T>C (VUS) and c.2731-2A>G (disease variant)) were identified to co-occur with the variant of interest in a subject undergoing ATP7B gene testing. These variants may explain WD phenotype, albeit phase of the variants would need to be assessed and c.1922T>C has not yet been classified as a disease variant. Taken together, this variant has been classified as a VUS-possibly benign.