Molecular genetic diagnosis of Wilson disease by ARMS-PCR in a Pakistani family.

Wilson disease is a rare autosomal recessive disorder caused by mutations in the ATP7B gene causing hepatic and neurological damage due to copper accumulation. Early diagnosis and treatment could lead to improved survival of patients. Patients are best treated at pre-symptomatic stages but early diagnosis of Wilson disease is challenging owing to complex diagnosis. Evidence based genetic counseling requires characterization of underlying mutations in Wilson disease families. The aim was to characterize the causative mutation(s) in a Pakistani Wilson disease family by custom developed ARMS-PCR assay. A proband (19 years old boy) having Wilson disease with evidence of K-F ring, severe neurological and psychiatric manifestations and clinical findings supported by biochemical abnormalities was followed. Following screening for 12 putative mutations in ATP7B, we identified a homozygous mutation (p.Cys271*, c.813C > A) in proband by T-ARMS-PCR assay and validated by Sanger DNA sequencing. Furthermore, on screening of his family members, a younger sister (aged 9 years) was found to have the same homozygous mutation even though she was clinically asymptomatic except for a light K-F ring. Parents were heterozygous for this mutation and an elder brother was homozygous normal. Molecular diagnosis by PCR based assays (M-ARMS-PCR and T-ARMS-PCR) is cost effective, reliable, and efficient for preliminary screening of mutations in the ATP7B gene in developing countries like Pakistan, which can be successfully applied to Wilson disease families for genetic testing and follow-up evidence based genetic counseling.