Which disease or disorder is caused by the inheritance of two mutated alleles?

The correct answer is: Cystic fibrosis

Cystic fibrosis is a medical condition where in the individual secrets thick mucus secretion obstructing respiratory pathway. It is an autosomal recessive disorder- mutation of both the copies of the gene inside a cell. As a result, the person has two mutated alleles. Gene responsible for this disease is CFTR gene.
Down syndrome comes under chromosomal disorder (change in structure of chromosome), hemophilia is caused due to alteration of single gene in chromosome X and color blindness is autosomal dominant disorder- one copy of altered gene is sufficient to cause the disease.

• Cystic fibrosis results in breathing disorder of the affected individual due to increased thick mucus secretion
• The disorder is caused due to alteration in CFRT gene
• It is a type of autosomal recessive disorder, having both copies of gene altered in a cell
• Other disorders mentioned are not autosomal recessive in nature