• Z chromosome

    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.

  • ZAP-70

    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 […]

  • Zebra

    ‘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.

  • Zygotic lethal gene

    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 […]

  • Zygote intrafallopian transfer (ZIFT)

    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 […]

  • Forensic medicine

    Forensic medicine: The branch of medicine dealing with the application of medical knowledge to establish facts in civil or criminal legal cases, such as an investigation into the cause and time of a suspicious death. Also known as forensic pathology.

  • Aase-Smith syndrome II

    Aase-Smith syndrome II: A genetic disorder that may be detected during early infancy and is characterized by the presence of three bones (phalanges) within the thumbs (triphalangeal thumbs) rather than the normal two and abnormally reduced production of red blood cells (hypoplastic anemia). The exact cause of the syndrome is unknown. However, most evidence suggests […]

  • Cardioversion

    Cardioversion: The conversion of a cardiac rhythm or electrical pattern to another, generally from an abnormal one to a normal one. Cardioversion can be accomplished by using medications or by electrical shock with a special defibrillator.

  • Typhus, epidemic

    A severe acute disease with prolonged high fever up to 40° C (104° F), intractable headache, and a pink-to-purple raised rash, due to infection with a microorganism called Rickettsia prowazekii. Among the other signs and symptoms of the disease are cough, dyspnea (difficulty breathing), vomiting, splenomegaly (enlargement of the spleen), hypotension (low blood pressure), and […]

  • Alpha-synuclein

    Alpha-synuclein: One in a family of structurally related proteins that are prominently expressed in the central nervous system. Aggregated alpha-synuclein proteins form brain lesions that are hallmarks of some neurodegenerative diseases (synucleinopathies). The gene for alpha-synuclein, which is called SNCA, is on chromosome 4q21. Defects in this protein are believed to be related to the […]