A disease caused by an autosomal primary non-disjunction is

Options

A. down's syndrome
B. klinefelter's syndrome
C. tuner's syndrome
D. sickle-cell anaemia

Answer

A

Explanation

Non-disjunction is the failure of chromosomes to disjoin or separate and move away to opposite poles. Non-disjunction of 21st chromosome during oogenesis is the cause of down's syndrome. It occurs due to the presence of an additional copy of chromosome no. 21 (trisomy of 21st chromosome) is humans.