Glossary
| Term | Description |
|---|---|
| Oligonucleotide | A short sequence of single stranded DNA or RNA. It is often used as a probe for detecting complementary DNA or RNA. |
| Omega-3 fatty acids | These are fats found in certain fish naturally and can lower blood cholesterol. Fish containing higher amounts of this fat are salmon, trout, mackerel, herring, halibut and albacore tuna in a can (packed in water). |
| Omega-6 fatty acids | These are unsaturated fats mostly found in vegetable oils that provide the essential fatty acids for good nutrition. |
| Omphalocele | A protrusion of a part of the intestine through a large opening in the abdominal wall at the site of the umbilicus. The protruding bowel is covered by a thin transparent membrane and 30 % of infants with an omphalocele are felt to have a chromosomal defect. |
| Oncogene | A gene capable of transforming normal cells into cancer cells. |
| Ophthalmologist | A medical doctor who specializes in eye and vision care. |
| Optic glioma | An optic glioma is a tumor of the optic nerve (the nerve which controls vision). This tumor, which is uncommon, usually appears in childhood and is first noticed because of poor or failing vision or bulging of the eye. Treatment for this condition includes surgery and radiation therapy. |
| Organelles | Organelles literally means "little organs". These are specialized structures found inside each cell that allow the cell to function properly. Examples of organelles include the nucleus, mitochondria, and lysosomes, but there are many other types of organelles. |
| Organic Acid Disorders | A group of conditions that cause organic acids to build up to toxic levels in the body. Usually this build-up is caused by an enzyme that is missing or not working properly. The defective enzyme stops the person from being able to metabolize (break down) food leading to an increase in organic acids that are toxic to the body. Organic Acid Disorders include: Methylmalonic Acidemia (MMA), Propionic Acidemia (PPA), Multiple Carboxylase Disorders, and Glutaric Acidurias (GA), among others.
The way Organic Acid Disorders are inherited is called autosomal recessive. |
| Orthopedist | A medical doctor who specializes in problems of the skeletal system (bones). |
| Osteogenesis Imperfecta (OI) | This condition is more commonly known as "brittle bone disease" as individuals with OI have bones that break very easily. This is caused by a disorder of type I collagen in which the collagen is either improperly formed or less than a normal amount is produced. There are 4 major classifications of OI:
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| Ovulation | The release of an egg from the ovary into the fallopian tube to be fertilized by a sperm about mid-point in a woman's 28 day menstrual cycle. |