<prompt> The gene for Wilson;s disease is onLong arm of Chromosome 13Long arm of Chromosome 6Sho arm of Chromosome 13Sho arm of Chromosome 6  <response>: In Wilson;s disease,the underlying defect lies in the long arm of chromosome 13 where there is a mutation in ATP7B gene,the normal hepatic copper- excreting gene.Eventually,capacity of hepatocytes to store copper is exceeded and copper is released into circulation which then gets deposited in extrahepatic tissues such as the brain eyes, and others. Reference:Textbook of pathology-Harsh Mohan,6th edition,page no:628 