Dictionary

HIB Haemophilus influenzae type B.

hiatal hernia See hernia, hiatal.

HHV Human herpesvirus. HHV-1 is herpes simplex type 1. HHV-2 is herpes simplex type 2. HHV-3 is herpes zoster, the cause of shingles. HHV-4 is the Epstein-Barr virus, the cause of infectious mononucleosis. HHV-5 is cytomegalovirus. See also human herpesvirus 6; human herpesvirus 7; human herpesvirus 8.

HHS The Department of Health and Human Services of the US government, which has jurisdiction over public health, welfare, and civil rights issues and is the highest-level US government body with such jurisdiction. Agencies under HHS include the Food and Drug Administration (FDA) and the National Institutes of Health (NIH).

HGV Hepatitis G virus. See hepatitis G.

hexoseaminidase A An enzyme whose deficiency causes Tay-Sachs disease. See also Tay-Sachs disease.

hexadactyly The presence of an extra digit: a sixth finger or toe. Hexadactyly is a very common birth defect. The sixth digit can be located in three different locations: on either side of the extremity or somewhere in between. With the hand, for example, the extra finger can be out beyond the little finger (ulnar…

hex-A deficiency Hexosaminidase A deficiency. See Tay-Sachs disease.

HEV Hepatitis E virus. See hepatitis E.

heterozygous Possessing two different forms of a particular gene, one inherited from each parent.

heterozygote An individual who has two different forms of a particular gene, one inherited from each parent. A heterozygote for cystic fibrosis (CF) has the CF gene on one chromosome 7 and the normal paired gene on the other chromosome 7. Also known as carrier.

heterosexuality Sexuality directed toward someone of the opposite sex.