Video Transcript
A couple have decided to have a
child. Which of the following diseases are
they most likely to be offered genetic screening for? (A) Malaria, a disease spread by
mosquitoes that act as vectors to carry the parasite Plasmodium. (B) Influenza, a viral disease that
usually causes a few days of fever, headaches, and nausea. (C) Tuberculosis, a bacterial
disease that infects the lungs. (D) Hemophilia, an X-linked disease
that prevents the blood from clotting.
This question is asking us about
genetic screening. Let’s discuss this in some detail
so we can choose the best answer to our question.
The DNA in our cells is responsible
for giving us many of our characteristics, such as eye or hair color, for
example. These characteristics are brought
about by genes, which are sections of DNA that contain the instructions for these
characteristics.
Unfortunately, we may also possess
genes that can cause certain diseases or disorders. Although we may not show these
disorders ourselves, our future children might. Genetic screening can be used to
look at our DNA for any changes that may be affected. This can help potential parents
decide if they want to go through a pregnancy or not.
For this question, the important
point to remember is that genetic screening is looking for changes in our genes that
can lead to genetic disorders. With this in mind, we can eliminate
answer choices (A), (B), and (C), because these are all diseases caused by
infectious pathogens and are not inherited in our DNA.
Hemophilia is a genetic disease
that is caused by an error in a gene on the X chromosome. This error can be passed on to any
potential offspring. So this can be screened for by
using genetic screening. Therefore, the option that
indicates a disease that can be screened for is given by answer choice (D):
hemophilia, an X-linked disease that prevents the blood from clotting.
