Question

Write a brief note on Down syndrome. (3 Marks)

Answer 1

• Down syndrome is the disorder arising due to chromosomal abnormality. (0.5 Marks)
• This is the first discovered and described the chromosomal disorder in human beings. (0.5 Marks)
• This disorder is characterized by the presence of 47 chromosomes. It is described as the trisomy of the 21st pair. (0.5 Marks)
• Infants with this disorder have one extra chromosome with the 21st pair in every cell of the body. Therefore, they have 47 chromosomes instead of 46. (0.5 Marks)
• Children suffering from Down syndrome are usually mentally retarded and have a short lifespan. Mental retardation is the most prominent characteristic. (0.5 Marks)
• Other symptoms include short height, short wide neck, flat nose, short fingers, scanty hair, single horizontal crease on palm and a life expectancy of about 16-20 years. (0.5 Marks)