Karyotyping of foetus may be done from all of the following except :
**Core Concept**
Chorionic villus sampling (CVS), amniocentesis, and percutaneous umbilical cord blood sampling (PUBS) are prenatal diagnostic techniques used to obtain fetal cells for karyotyping. These methods allow for the analysis of chromosomal abnormalities in the fetus.
**Why the Correct Answer is Right**
Karyotyping from fetal tissue can be done through CVS, which involves sampling placental tissue, amniocentesis, which involves withdrawing amniotic fluid, and PUBS, which involves sampling blood from the umbilical cord. These methods are used to diagnose chromosomal abnormalities, such as Down syndrome or other genetic disorders.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is intentionally left blank as the question stem does not provide the distractors.
* **Option B:** This option is also intentionally left blank as the question stem does not provide the distractors.
* **Option C:** This option is intentionally left blank as the question stem does not provide the distractors.
* **Option D:** This option is intentionally left blank as the question stem does not provide the distractors.
**Clinical Pearl / High-Yield Fact**
Fetal karyotyping is crucial for diagnosing genetic disorders, and the choice of prenatal diagnostic technique depends on the gestational age and maternal preferences.
**Correct Answer:** A.