Wilson disease (WD) is difficult to diagnose, and because early identification can avoid all symptoms, knowing the precise prevalence was critical for evaluating the cost-effectiveness of a screening program. Because the group included a large number of patients with WD, researchers sought to assess prevalence by measuring the carrier frequency for clinically relevant ATP7B mutations.

To assess the prevalence, 1661 patients with Gran Canaria ancestry were screened for the most common mutation, and the frequency of additional variants was approximated from medical records. Alternatively, ATP7B mutations were found in exomes and genomes from 851 Canarians, 236 from Gran Canaria, and a public Spanish exome database. The estimated carrier frequencies in Gran Canaria ranged from 1 in 20 to 28, depending on the technique utilized, resulting in prevalences ranging from 1 case per 1547 to 3140 patients. Alternatively, the predicted impacted frequencies in the archipelago were 1 in 5985 to 7980 and 1 in 6278 to 16,510 in mainland Spain, respectively.

The number of carriers predicted significantly greater prevalences than reported, implying that WD was underdiagnosed; particular mutations might go undiagnosed due to limited penetrance or no indications of illness at all; To approach preventative screening in the asymptomatic population, cost-efficacy models should reflect regional prevalence rather than national prevalence, and genetic screening methodologies will need to cope with the genetic variability of ATP7B in the general population and in patients.