A sex chromosome in certain animals, such as chickens, turkeys, and moths. In humans, males are XY and females XX, but in animals with a Z chromosome, males are ZZ and females are WZ.

Zeta-chain-associated protein kinase 70. A member of the protein tyrosine kinase family, ZAP-70 is normally expressed in T cells and natural killer cells and has a critical role in the initiation of T-cell signaling. ZAP-70 is expressed in T cells and tumors of T-cell lineage. A high level of ZAP-70 expression appears restricted to T-cell […]

‘When you hear hoof beats, think of horses, not zebras.’ For example, when someone develops a mild transient cough, a virus infection is the most logical and likely cause, and tuberculosis is a zebra.

A gene that is lethal (fatal) for the zygote, the cell formed by the union of a sperm (male sex cell) and an ovum (female sex cell). The zygote would normally develop into an embryo, as instructed by the genetic material within the unified cell. However, a zygotic lethal gene scotches prenatal development at its […]

A technique in which a woman’s egg is fertilized outside the body, then implanted in one of her fallopian tubes. This technique is one of the methods used to overcome infertility, the inability of couples to produce offspring on their own. First, the egg and the male sperm needed to fertilize it are harvested. Then […]

A small gland that is located near the center of the brain. This gland secretes melatonin, and it may therefore be part of the body’s sleep-regulation apparatus. Also known as pineal body.

Ankyrin deficiency: Known also as hereditary spherocytosis (HS), this is a genetic disorder of the red blood cell membrane clinically characterized by anemia, jaundice (yellowing) and splenomegaly (enlargement of the spleen), due to deficiency of ankyrin, a protein in the membrane of the red cell. In HS the red cells are smaller, rounder, and more […]

Violence involving young persons, typically children, adolescents, and young adults between the ages of 10 and 24. The young person can be the victim, the perpetrator, or both. Youth violence includes aggressive behaviors such as verbal abuse, bullying, hitting, slapping, or fistfighting. These behaviors have significant consequences but do not generally result in serious injury […]

Familial Parkinson disease type 9.

Fear of insects: An abnormal and persistent fear of insects. Sufferers of this fear experience undue anxiety even though they realize that most insects pose no threat. To avoid insects, they may frequently clean rooms and carpets, sweep hallways, spray insect-killer or seal off doors and windows. “Entomophobia” is derived from the Greek “entomos” (insect) […]