Question

Write a brief note.

Down syndrome

Answer 1

Down syndrome is a disorder arising due to chromosomal abnormality. This is the first discovered and described chromosomal disorder in human beings. This disorder is characterised by the presence of 47 chromosomes. It is described as trisomy of the 21^st chromosome. Infants with this disorder have one extra chromosome with the 21^st pair in every cell of their body. Therefore they have 47 chromosomes instead of 46. Children suffering from Down’s syndrome are usually mentally retarded and have a short lifespan. Mental retardation is the most prominent characteristic. Other symptoms include short height, short wide neck, flat nose, short fingers, scanty hair, single horizontal crease on palm, and a life expentancy of about 16–20 years.