Question

Down's syndrome is

• A. autosomal abnormality
• B. sex chromosomal abnormality
• C. sex-linked disease
• D. None of the above

Answer 1

Answer: (A)

autosomal abnormality

Answer 2

Down's syndrome is autosomal abnormality. It arises due to trisomy of $21^{st}$ chromosome, ie, total $47$ chromosomes will be present in the person. It is also called Mongolian idiocy. The syndrome was reported first time by an English physician John Langdon Down in $1866$. The main features are mental deficiency, sound face, small ears, protruding tongue etc.