rare ... see also overview of Chediak-Higashi Syndrome.
Chediak-Higashi Syndrome is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Chediak-Higashi Syndrome, or a subtype of Chediak-Higashi Syndrome, affects less than 200,000 people in the US population.
Ophanet, who are a consortium of European partners, currently defines a condition rare when if affects 1 person per 2,000. They list Chediak-Higashi Syndrome as a "rare disease". More information about Chediak-Higashi Syndrome is available from Orphanet
16 MEDICAL BOOKS ONLINE! Review excerpts from medical books online, free, without registration, for more information about the prevalence and/or incidence of Chediak-Higashi Syndrome.
This deficiency’s primary cause is a diet lacking in vitamin C-rich foods, such as citrus fruits, tomatoes, cabbage, broccoli, spinach, and berries. Because the body can’t store this water-soluble vitamin in large amounts, the supply needs to be replenished daily. Other causes include:
❑ destruction of vitamin C in foods by overexposure to air or by overcooking
❑ excessive ingestion of vitamin C during pregnancy, which causes the neonate to require large amounts of the vitamin after birth
❑ marginal intake of vitamin C during periods of physiologic stress — caused by infectious disease, for example — which can deplete tissue saturation of vitamin C.
Historically common among sailors and others deprived of fresh fruits and vegetables for long periods of time, vitamin C deficiency is uncommon today in the United States, except in alcoholics, people on restricted-residue diets, and infants weaned from breast milk to cow’s milk without a vitamin C supplement.
Source: Professional Guide to Diseases (Eighth Edition), 2005
Typically, oversecretion of human growth hormone (hGH) produces changes throughout the body, resulting in acromegaly and, when oversecretion occurs before puberty, gigantism. Eosinophilic or mixed-cell adenomas of the anterior pituitary gland may cause this oversecretion but the etiology of the tumors themselves remains unclear. Occasionally, hGH levels are elevated in more than one family member, which suggests the possibility of a genetic cause.
The earliest clinical manifestations of acromegaly include soft-tissue swelling of the extremities and coarsening of facial features. This rare form of hyperpituitarism occurs equally among males and females, usually between ages 30 and 50. Annually, it affects 3 to 4 people per every million.
In gigantism, proportional overgrowth of all body tissues starts before epiphyseal closure. This causes remarkable height increases of as much as 6"(15 cm) per year. Gigantism affects infants and children, causing them to attain as much as three times the normal height for their age. As adults, they may ultimately reach a height of more than 80"(203 cm). Gigantism is rare; there have only been 100 reported cases.
Source: Professional Guide to Diseases (Eighth Edition), 2005
Oculocutaneous albinism results from autosomal recessive inheritance; ocular albinism, from an X-linked recessive trait that causes hypopigmentation only in the iris and the ocular fundus.
Normally, melanocytes synthesize melanin. Melanosomes, melanin-containing granules within melanocytes, diffuse and absorb the sun's ultraviolet light, thus protecting the skin and eyes from its dangerous effects. In tyrosinase-negative albinism (the most common type), melanosomes don't contain melanin because they lack tyrosinase, the enzyme that stimulates melanin production. In tyrosinase-positive albinism, melanosomes contain tyrosine, a tyrosinase substrate, but a defect in the tyrosine transport system impairs melanin production.
In tyrosinase-variable albinism (rare), an unidentified enzyme defect probably impairs synthesis of a melanin precursor. Other rare forms of albinism are Chédiak-Higashi syndrome (tyrosine-negative albinism with hematologic and neurologic manifestations); Hermansky-Pudlak syndrome (tyrosinase-positive albinism with platelet dysfunction, bleeding abnormalities, and ceroidlike inclusions in many organs); and Cross-McKusick-Breen syndrome (tyrosinase-positive albinism with neurologic involvement).
In the United States, both types of albinism are more common in Blacks than in Whites. Native Americans have a high incidence of the tyrosine-positive form.
Source: Professional Guide to Diseases (Eighth Edition), 2005
Source: The 5-Minute Pediatric Consult, 2008
The term 'prevalence' of Chediak-Higashi Syndrome usually refers to the estimated population of people who are managing Chediak-Higashi Syndrome at any given time. The term 'incidence' of Chediak-Higashi Syndrome refers to the annual diagnosis rate, or the number of new cases of Chediak-Higashi Syndrome diagnosed each year. Hence, these two statistics types can differ: a short-lived disease like flu can have high annual incidence but low prevalence, but a life-long disease like diabetes has a low annual incidence but high prevalence. For more information see about prevalence and incidence statistics.
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