Question

Mongolian idiots are due to trisomy in chromosome number 21 is called as
A. Down's syndrome
B. Turner's syndrome
C. Klinefelter’s syndrome
D. Triplex syndrome

Answer 1

Hint: Mongolian idiocy was used to describe a certain form of mental illness, usually linked to genetic disability. It was the outdated term for a person with this syndrome. Trisomy is the condition in Aneuploidy where an additional chromosome is observed in an individual.

Complete answer: Chromosomes are threadlike structures present in the nucleus that contain genes transmitted from parents to offsprings. The arrangement and the number of chromosomes of each species are specific. Due to certain abnormalities, structural changes in the number of chromosomes can occur during cell division. There can also be numerous anomalies with the least modifications. Changes in the entire chromosome are classified as chromosome aberrations.
a) Aneuploidy: It is the loss or gain of a chromosome. It occurs due to non-disjunction of chromatids when chromatids fail to differentiate during cell division. This results in two copies of the chromosome in one gamete and no chromosome in the other.
b) Trisomy: The cell has one additional chromosome. Down syndrome is a deficiency in autosomes. They have a short, round, furred tongue, partially open mouth, big palm with a palm plunger. The effects are short. They are sometimes referred to as mongolism or Mongol idiocy. They are vulnerable to heart disease and respiratory problems.
Hence, the correct answer is option A.

Note: The parents of the affected individual are usually genetically normal. The probability increases from less than 0.1% in 20-year-old mothers to 3% in those of age 45. The extra chromosome is believed to occur by chance, with no known behavioural activity or environmental factor that changes the probability.