Webster's New World Medical Dictionary

Rothmund-Thomson syndrome
A hereditary
disease that is characterized by progressive effects
on multiple areas of the body, including the skin,
hair, eyelashes, teeth, musculoskeletal system,
blood, and eyes. Patients have an increased risk for
developing cancer, especially osteosarcoma and
skin cancer. Abbreviated RTS. RTS is inherited as an
autosomal recessive trait and is caused by mutations
in the RECQL4 gene on chromosome 8. This gene
encodes a DNA helicase, an enzyme that promotes
DNA unwinding, which permits many basic cellular
processes to take place. Also known as poikilo-
derma congenita and poikiloderma atrophicans
with cataract.
roundworm
A type of parasitic worm that
hatches in the intestines and lives there. The eggs of
the roundworm usually enter the body through con-
taminated water or food or on fingers placed in the
mouth after the hands have touched a contaminated
object. Symptoms of roundworm infections include
fatigue, weight loss, irritability, poor appetite,
abdominal pain, and diarrhea. Treatment with med-
ication results in a cure in about a week. Without
treatment, anemia and malnutrition can develop. An
example of a roundworm is Trichuris trichiura, also
known as the human whipworm. This worm is
found worldwide, but infections are most frequent
in areas with tropical weather and poor sanitation
practices, and among children. Infection with T.
trichiura is not foreign to the US; it occurs in the
southern US.
RPR test
Rapid plasma reagin test. See 
syphilis
test, RPR.
rRNA
Ribosomal RNA. See 
RNA, ribosomal.
RSV 1
Respiratory syncytial virus.
2
Rous sar-
coma virus, a virus that is the cause of a serious
form of soft tissue cancer called sarcoma.