Author: Glossary

Hutchinson-Gilford progeria syndrome is a very rare progressive disorder characterized by an appearance of accelerated aging in children (National Organization for Rare Disorders [NORD], 2000). Progeria is a Greek term meaning “prematurely old.” The classic type is Hutchinson- Gilford progeria syndrome, first described in England in 1886 by Jonathan Hutchinson and again in 1886 and…

Hunter syndrome (mucopolysacchridosis II, or MPS II), a progressive disorder arising from a deficiency in the enzyme iduronate sulfatase, is a sex-linked inborn error of metabolism (IEM) affecting only males. The enzyme’s absence or deficiency prevents complete breakdown of the mucopolysacchrides heparen sulphate and dermatan sulfate, which then accumulate in bodily cells. One of a…

Holt-Oram syndrome, also known as heart-hand syndrome or cardiac-limb syndrome, refers to a rare genetic condition involving abnormalities of the heart and upper limbs. Those affected have malformations or abnormalities of the bones in the thumbs, wrists, and arms, but lower extremities are not affected. Bones may be missing, extra, underdeveloped, or malformed. There may…

Hermansky-Pudlak syndrome (HPS), which was first described in 1959 and is named after its discoverers, is characterized by a rare form of albinism that is associated with low visual acuity, bruising and prolonged bleeding, lung fibrosis, and occasionally inflammatory bowel disease and reduced kidney function (National Institute of Child Health and Development [NICHD], 2002). A…

Hereditary spastic paraplegia (HSP; also known as hereditary spastic paraparesis, Strumpell disease, Striimpell- Lorrain disease, hereditary Charcot disease, hereditary progressive spastic paraplegia, and French settlement disease) is a label used to represent a group of inherited degenerative spinal cord disorders characterized by a slow, gradual, progressive weakness and spasticity (stiffness) of the legs.  

Hemophilia is a bleeding disorder in which there is a deficiency of selected proteins in the body’s blood-clotting system. “Clotting is the process by which your blood changes from a liquid to a solid state in order to stop bleeding”. There are three main types of hemophilia in which a different clotting factor is missing…

Hemophilia is a sex-linked inherited disorder in which the individual lacks the necessary blood-clotting factors to stop bleeding. The condition is transmitted via the X chromosome, but it is believed that some individuals are affected by hemophilia due to mutation of the genes on that chromosome. There are two forms of hemophilia: Type A (with…

Hemispherectomy is a surgical procedure involving the removal of “a cerebral hemisphere, including the frontal, temporal, parietal, and occipital lobes while leaving intact parts of the thalamus and basal ganglia”. A hemispherectomy may be performed as a treatment for severe seizure disorders, fatal tumors, hemiplegia, and Rasmussen encephalitis. The procedure is usually reserved as a…

Hecht syndrome (HS) is a rare, hereditary disorder of muscle development and mechanics. The first case report appeared in 1968. Subsequently, several affected individuals in an extended family group were described.