Glossary

Canavan disease

Canavan disease is a rare, inherited, neurological disorder characterized by spongy degeneration of the brain, in which the white matter is replaced by microscopic fluid-filled spaces. It is caused by a deficiency of an enzyme called aspartoacylase. Symptoms of Canavan disease, which appear in early infancy and progress rapidly, may include mental retardation, loss of previously acquired motor skills, feeding difficulties, abnormal muscle tone, poor head control, and megalocephaly (abnormally enlarged head). Death usually occurs by age four.

All donors of Jewish ancestry are tested for the mutations that cause Canavan disease.

Cystic fibrosis (CF)

CF is an inherited disease caused by an abnormal protein that does not allow the normal passage of salt into and out of certain cells, including those that line the lungs and pancreas. As a result, these cells produce thick, sticky mucus and other secretions. The mucus clogs the lungs, causing breathing problems. Affected individuals also have frequent lung infections, which eventually damage the lungs and contribute to early death. The thickened digestive fluids made by the pancreas are prevented from reaching the small intestine, where they are needed to digest food.

To inherit CF, a child must receive two CF genes, one from each parent who “carries” a CF gene. A carrier has one normal gene and one abnormal gene in the pair, and is as healthy as a non-carrier. When both parents carry an abnormal CF gene, there is a 25% chance that the child will have CF.

While all racial groups are affected, the disease is most common in Caucasian individuals. If indicated in their family / genetic history, donors are tested for the CF gene.

Cytomegalovirus (CMV)

CMV is a common virus that infects between 50% and 85% of adults in the United States by 40 years of age, but rarely causes obvious illness. It is a member of the herpes virus family. Other members of the herpes virus family cause chickenpox, infectious mononucleosis, fever blisters (herpes I) and genital herpes (herpes II) . Once a person becomes infected, the virus remains alive, but usually dormant within that person's body for life. Recurrent disease rarely occurs unless the person's immune system is suppressed due to therapeutic drugs or disease. Therefore, for the vast majority of people, CMV infection is not a serious problem. The virus is carried by people and is not associated with food, water or animals.

Anyone can become infected with CMV. Almost all people have been exposed to CMV by the time they reach adulthood.

Although the virus is not highly communicable, it can be spread from person to person by direct contact. The virus is shed in the urine, saliva, semen and to a lesser extent in other body fluids. Transmission can also occur from an infected mother to her fetus or newborn and by blood transfusion and organ transplants.

Semen analysis

The purpose of semen analysis is to evaluate a semen sample with respect to factors affecting fertility. The factors determined by a semen analysis include:

1. Determination of sperm concentration: The sperm concentration of an ejaculate is measured by a count of how many million sperm are contained per milliliter of ejaculate.

2. Motility and progression: The motility of a sample is determined by calculating the concentration of motile (living) sperm versus nonmotile (dead) sperm. The progression of a sample is measured on a scale of 0-3+ as follows:

   Level	Description
   0	No motion of sperm
   1	Sperm moving; no forward motion visible
   1+	Sperm moving vigorously but without any visible forward progression
   2-	Sperm moving with meandering; slow forward progression
   2+	Sperm moving more direct; slow forward motion
   3	Sperm moving in straight line with good speed
   3+	Sperm moving in a straight line with excellent speed

3. Morphology: Morphology analysis is performed on all specimens of fertility enhancement, fertility insurance, and direct donor depositors. Anonymous donors are assessed during each screening sample and periodically during the duration of the donation period of the donor. Morphology is analyzed by an evaluation of a random sample of 100 sperm cells. These cells are classified as: normal, abnormal, small, large, pyriform, duplicated, tapered, and tail defect.
4. Evaluation of extracellular artifacts: Extracellular artifacts can be visualized during microscopic evaluation. These artifacts include round cells, white blood cells, epithelial cells, granules, cellular debris, and urine crystals.

5. Cryosurvival: Cryosurvival is the re-examination of stored semen specimens after they have been frozen and thawed to asses approximately how well the semen will survive for long-term storage. A post-thaw unit is analyzed the day following the donation. The formula to obtain the cryosurvival is:

   Cryosurvival = (Post Thaw Motility % / Initial Motility %)
   Remainder = Initial Motility = [# alive / # total (alive and dead)]

Sickle-cell disease

Sickle-cell disease is an inherited disease of red blood cells which is more common among individuals of African ancestry. Sickle cell disease the hemoglobin in red blood cells, which causes attacks of pain, damage to vital organs, risk of serious infections and can lead to early death. The disease occurs when a person inherits one sickle cell gene from each parent or a combination of one sickle cell gene plus one of several other abnormal hemoglobin genes. All donors with African ancestry are screened for the sickle cell trait.

Tay-Sachs disease

Tay-Sachs disease is a fatal inherited disease of the central nervous system that begins in infancy, usually within 4 to 6 months of age, in which an enzyme deficiency leads to the accumulation of gangliosides in the brain and nerve tissue, resulting in mental retardation, convulsions, blindness, and, and typically results in death by age 5. Babies with Tay-Sachs lack the protein enzyme called hexosaminidase A (hex A) necessary for breaking down certain fatty substances in brain and nerve cells. These substances build up and gradually destroy brain and nerve cells, until the entire central nervous system cease to function.

Tay-Sachs carriers have one normal gene for hex A and one Tay-Sachs gene. The carrier does not have the illness and leads a normal, healthy and full life. However, when two carriers become parents: There is a 25% chance that any child they have will inherit a Tay-Sachs gene from each parent and have the disease. There is a 25% chance that the child will inherit the normal gene from each parent and be completely free of the disease and the Tay-Sachs gene. There is a 50% chance that the child will inherit one of each kind of gene and be a carrier like the parents and free of disease. If only one parent is a carrier, none of their children can have the disease, but each child has a 50-50 chance of inheriting the Tay-Sachs gene and being a carrier.

The Tay-Sachs carrier screen is performed on donors of Jewish and French-Canadian ancestry.

Thalassemia

A thalassemia carrier screen is performed on donors of Mediterranean origin using a diagnostic test procedure called hemoglobin electrophoresis. Hemoglobin is the protein in our red blood cells that carries oxygen and nutrients to all parts of the body.

Thalassemia is a genetic blood disorders that affect a person's ability to produce the hemoglobin molecule. Thalassemia is an inherited disease, which means it is passed on from parents to their child through their genes. Both parents must have the thalassemia trait in order to pass the disease on to their child, but it only takes one parent to pass the trait onto his/her child. The thalassemia trait will never develop into disease. Thalassemia trait can be passed on for many generations without being detected before a child is born with disease.