Expert: Florence M Rollwagen - 11/10/2008

Question
i need help in describing the biological basis of flu and down syndrome...i need to know how the body responds to flu,and how 3 of the different signs
and symptoms of flu are produced and displayed.
could you possibly tell me what the difference is between signs and symtoms of
flu...
and also do you know why people with down syndrome have certain physical
features such as upward slant to eyes etc...i
cnt seem to find much information on the internet so i was wondering if u
would be able to help me please.thanks

Answer
Hi Muriam:  Thanks for your question.

Signs and symptoms of any condition differ by who is doing the observing.  A sign is something that an observer (doctor) can see with testing, like high blood pressure or low blood count.  A symptom is something the patient feels, as in: I'm dizzy when I stand up.

Some of the symptoms of flu can be that "blah" feeling like you want to lie down.  Sometimes a fever is also present.  Runny nose and/or chest congestion may also be present.

The signs are similar, and include chest X-ray differences, elevated white blood cell count, etc.

Down syndrome is caused by an extra chromosome 21 in the child.  The person doesn't need the entire extra chromosome 21, if only a broken part is carried as extra material, the condition may occur. The signs and symptoms of Down syndrome are caused by the extra genetic material carried on chromosome 21.  There are many genes on this chromosome, some of which code for control gene regulators, such as DSCR1 and DYRK1A.  These genes control the production of proteins by other genes, and it is the build up of extra proteins that leads to the condition.  Studies in mice suggest that other genes may also be involved, but they are not known yet.

Experiments in where extra genes from chromosome 21 are cloned into mouse embryos showed some facial abnormalities, desire for companionship and weak muscles, all characteristics of Down syndrome.  All the signs were not met, however, leading scientists to think that more genes are also involved.

Here is more information:
http://en.wikipedia.org/wiki/Down_syndrome

Hope this helps!

FM Rollwagen, PhD