A phenotypically normal woman marries a man with Wilson disease,an autosomal recessive disorder.They have a son who has Wilson disease.If you need two copies of the recessive allele to be affected and the mother doesn't have the disease,how did the son get it?

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Quizplus · Accepted Answer

If the mother is phenotypically normal, it means she doesn't have the disease, which eliminates options A and C. As Wilson disease is autosomal recessive, the son must have inherited two copies of the recessive allele – one from each parent. Since the father has Wilson disease, we know he must have two copies of the recessive allele. Therefore, the only way the son could have inherited the disease is if the mother was a carrier of one recessive allele and one normal allele, as stated in option B. This would result in a 25% chance of their offspring inheriting two copies of the recessive allele and hence, having Wilson disease. Option D and E are also incorrect as they refer to dominant alleles, which are not relevant in an autosomal recessive disorder.

A Phenotypically Normal Woman Marries a Man with Wilson Disease,an