Question

Name any two syndromes caused due to chromosomal abnormality in humans and mention the abnormality in each case. Describe the physical (body) symptoms related to any one of these syndromes.

Answer 1

Two syndromes caused due to chromosomal abnormality in humans are Down’s syndrome and Klinefelter’s syndrome. Down’s syndrome is caused by trisomy of chromosome 21, meaning there is an extra chromosome 21 (47 chromosomes instead of 46). Klinefelter’s syndrome occurs due to the presence of an extra X chromosome in a male (XXY).

Physical symptoms of Down’s syndrome include mental retardation, prominent foreheads, flattened nasal bridge, habitually open mouth, projecting lower lips, a large protruding tongue, and a characteristic skin fold at the corner of the eyes. These children often have a short, stocky body, a short fifth finger with a single crease on the palm, and may have congenital heart defects. They are usually floppy when handled and have a happy disposition with good sense of humor.

Klinefelter’s syndrome males typically have underdeveloped genitalia (testes), sparse body hair, some breast development, long legs and arms, are mentally defective and sterile.