The problem is as following:
Primary Ciliary Dyskinesia (PCD) is caused by an autosomal recessive gene. 50% of patients with PCD also have Kartagener Syndrome. Josh has Kartagener Syndrome. What is the chance his brother or sister also have this syndrome?
A 0% B 6.3% C 12.5% D 25% E 50%
Is this problem actually solvable without knowing the alleles combination of the parents? The answer states C, but perhaps I´m missing something here.