Question

What is aneuploidy? Write any four symptoms of Down’s syndrome.

Answer 1

Hint: Aneuploidy is a genetic condition related to the long arm of the 21^st chromosomes (autosomal chromosome). An extra or missing chromosome is the common cause of such types of genetic disorders.

Complete answer:
Aneuploidy is a genetic condition, which occurs due to the presence of the abnormal number of chromosomes in a cell. The person with this condition bears three copies of chromosome 21, which is an autosomal chromosome. The disease caused due to aneuploidy is known as Down’s syndrome.
The four symptoms associated with Down's syndrome are speech disability, short stature, mental retardation, and skin folds.
- Mostly in case of aneuploidy, miscarriage happens in the woman.
- About 68% of cancer patients are aneuploidy.
- Genetic diseases with extrachromosomal defects are generally found in X, Y, 13, 18, and 21st chromosome.
- The trisomy of the 13^th chromosome results in Patau syndrome while in the 18^th chromosome results in Edward syndrome.
- At least 1 out of 160 human births is diagnosed with genetic defects.
- Features of Down’s syndrome:
1. The average IQ of a young adult diagnosed with Down’s syndrome is 50, which is equivalent to the mental ability of an 8- or 9-year-old child.
2. The parents are genetically normal while the offspring is abnormal.
3. The extra chromosomes at the 21$^{st}$ chromosome are believed to occur by random chance, with no known behavioral activity or environmental factor that changes the probability.

Note: Agents that are capable of causing aneuploidy are known as aneuploidies. Many of the harmful mutagenic carcinogens are aneuploidies. For example, X- rays may cause aneuploidy by fragmenting the chromosome and disrupting the spindle apparatus. Chemicals such as colchicine (mitotic poison) can also produce aneuploidy by affecting microtubule polymerization (chains formation).