Question

Which human genetic condition is characterized by trisomy 21 and results from chromosomal mutation?

Options

• Sickle cell anaemia

• Down's syndrome

• Huntington's disease

• Cystic fibrosis

Answer 1

Down's syndrome, also known as Trisomy 21, is a chromosomal mutation resulting from the presence of three copies of chromosome 21 instead of the normal two. This numerical chromosomal aberration (aneuploidly) is a classic example of how chromosomal mutations affect the phenotype and is one of the most common chromosomal disorders in humans.