Which of the following diseases cannot be detected in a developing foetus by amniocentesis?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Anaemia
Amniocentesis is a test done during pregnancy. A little of the amniotic fluid around the foetus is taken out, and the foetal cells and dissolved substances in it are studied. It can show genetic disorders, which are caused by faulty genes or chromosomes.
Option (1) Down syndrome — Can be detected. It is a chromosomal disorder with an extra copy of chromosome 21, which shows up in the foetal cells.
Option (2) Anaemia — Cannot be detected. Plain anaemia is a fall in haemoglobin, usually from poor nutrition such as lack of iron. It is not a genetic disorder of the foetus, so amniocentesis cannot show it.
Option (3) Sickle-cell anaemia — Can be detected. It is a Mendelian (gene) disorder in which a faulty gene changes haemoglobin. Unlike plain anaemia, it is inherited.
Option (4) Haemophilia — Can be detected. It is a sex-linked recessive gene disorder in which blood does not clot properly.
NCERT Extract:
Reproductive Health – Problems and Strategies – “… Statutory ban on amniocentesis for sex-determination to legally check increasing menace of female foeticides, massive child immunisation, etc., are some programmes that merit mention in this connection. In aminocentesis some of the amniotic fluid of the developing foetus is taken to analyse the fetal cells and dissolved substances. This procedure is used to test for the presence of certain genetic disorders such as, down syndrome, haemoplilia, sickle-cell anemia, etc., determine the survivability of the foetus.”