Question

Testing and screening for genetic diseases are done in a number of ways. Which of the following statements is true of genetic testing and screening?

	A.	Down Syndrome can be detected through a maternal blood test; alphafetoprotein levels tend to be altered in women carrying a fetus with Down Syndrome.
	B.	All of the other choices are true of genetic screening and testing programs.
	C.	Phenylketonuria screening is decreasing in commonality in the United States as incidence decreases in the population.
	D.	Chorionic Villus Sampling is the safest and most risk-free method of prenatal testing available for expecting mothers.

Answer 1

Option A-Down Syndrome can be detected through a maternal blood test; alphafetoprotein levels tend to be altered in women carrying a fetus with Down Syndrome.

Down syndrome is a Chromosomal disease in which there is Additional chromosome 21.(Trisomy 21)

*Down syndrome can be detected by using chromosmal Test using Blood test.This test can detect Down syndrome in Child because mother's blood carries DNA from the fetus,it may show extra chromosome 21 material indicating Down syndrome.For the confirmation of Diagnosis,other invasive tests are used.

Also,In most of pregnancies with a Down's syndrome  fetus, the  alpha-fetoprotein (AFP) measured in maternal serum & amniotic fluid is usually lessthan 70 per cent of the level attained in normal pregnancies.

Option C- False.

Phenyl Ketonuria is a common disease in USA.So the Use Phenyl Ketonuria screening is high(1 in 10,000-15,000),so that there is Early detection of the disease & the treatment is started Early so that It can be Controlled.

Option D -False

The non Invasive And safest method for prenatal Screening is Ultra sound.

Chorionic Villus sampling(CVS)is an Invasive test,Eventhough Safe in some case it may have some serious side effects-Like Miscarriage (1 in 100 )