no, it is caused by a triplication of the 21st chromosome.
Down syndrome is caused by the presence of a third chromosome 21
The pathogen Streptococcus causes Strep throats.
yes it causes childlike symptoms
Chikungunya virus is not important as it causes illness in human body. Chikungunya virus is an pathogen that causes a syndrome with symptoms, such as fever, headache, joint pain and chills.
A pathogen causes infectious disease. For instance, influenza virus is the pathogen that causes flu.
"Pathogen" means something that causes sickness (path- = suffering, gen- = creation). "HIV" stands for "Human Immunodeficiency Virus," which is a virus which sometimes, in time, causes the disease AIDS ("Acquired Immune Deficiency Syndrome"). In other words, HIV is the pathogen, and being infected by HIV is the cause of the disease AIDS.The best ways to avoid being infected by HIV is never ever to share needles for drugs, and never ever to have penetrative sex without a condom. If you steer clear of those, as long as you live in part of the world where HIV isn't endemic, you are likely safe from HIV.There is no cure for HIV infection or AIDS, but there are very effective treatments.
There are many causes of retardation. These includes Down syndrome, velocariofacial syndrome, fetal alcohol syndrome, problems during pregnancy and other genetic disorders.
Having an extra copy of chromosome 21. You are supposed to have 2; when you have 3 (trisomy 21), Down's Syndrome is the result.
See the Related Link to a very good FAQ on the causes of Down syndrome.
SARS is not a pathogen, it is an syndrome similar to AIDS. It is caused by a virus called coronavirus, but it is the mutated strain.
Down syndrome is purely genetic. There are no known environmental causes of the disorder. It is not a disease that is passed from parent to child. It is simply an disorder when the chromosomes split during cell division during development. The mayoclinic describes the causes: http://www.mayoclinic.com/health/down-syndrome/DS00182/DSECTION=causes