Epidemiology and introduction to the clinical presentation of Wilson disease.

Our understanding of the epidemiology of Wilson disease has steadily grown since Sternlieb and Scheinberg's first prevalence estimate of 5 per million individuals in 1968. Increasingly sophisticated genetic techniques have led to revised genetic prevalence estimates of 142 per million. Various population isolates exist where the prevalence of Wilson disease is higher still, the highest being 885 per million from within the mountainous region of Rucar in Romania. In Sardinia, where the prevalence of Wilson disease has been calculated at 370 per million births, six mutations account for around 85% of Wilson disease chromosomes identified. Significant variation in the patterns of presentation may however exist, even between individuals carrying the same mutations. At either extremes of presentation are an 8-month-old infant with abnormal liver function tests and individuals diagnosed in their eighth decade of life. Three main patterns of presentation have been recognized - hepatic, neurologic, and psychiatric - prompting their presentation to a diverse range of specialists. Deviations in the family history from the anticipated autosomal-recessive mode of inheritance, with apparent "pseudodominance" and mechanisms of inheritance that include uniparental isodisomy (the inheritance of both chromosomal copies from a single parent), may all further cloud the diagnosis. It can therefore take the efforts of an astute clinician with a high clinical index of suspicion to clinch the diagnosis of this eminently treatable condition.