Down syndrome is caused by which type of factors?

Down syndrome is caused by which type of factors?

• A. Environmental
• B. Genetic
• C. Nutritional
• D. Infectious

Answer: (B)

Down syndrome is a genetic condition caused by an extra copy of chromosome 21, a situation known as trisomy 21. The most common mechanism is nondisjunction during the formation of eggs or sperm, which leads to a gamete with an extra chromosome that, when joined with a normal gamete, results in the child having three copies of chromosome 21 in most or all cells. In a smaller number of cases, Down syndrome arises from a translocation of part of chromosome 21 or from mosaicism, both of which are still genetic in origin. Environmental exposures, nutritional factors, and infections during pregnancy do not cause Down syndrome, though maternal age is associated with a higher risk due to increased chances of meiotic nondisjunction. So, the factors underlying Down syndrome are genetic.

Down syndrome is a genetic condition caused by an extra copy of chromosome 21, a situation known as trisomy 21. The most common mechanism is nondisjunction during the formation of eggs or sperm, which leads to a gamete with an extra chromosome that, when joined with a normal gamete, results in the child having three copies of chromosome 21 in most or all cells. In a smaller number of cases, Down syndrome arises from a translocation of part of chromosome 21 or from mosaicism, both of which are still genetic in origin. Environmental exposures, nutritional factors, and infections during pregnancy do not cause Down syndrome, though maternal age is associated with a higher risk due to increased chances of meiotic nondisjunction. So, the factors underlying Down syndrome are genetic.