There are 2 types of Congenital Adrenal Hyperplasia
1.Classic Congenital Adrenal Hyperplasia
- the more severe form of the disease affecting very young children
2.Non-classic congenital adrenal hyperplasia
- a milder form that usually develops in late childhood or early adulthood.
Both classic and nonclassic forms of the disease are caused by deficiencies in the adrenal enzymes that are used to synthesize glucocorticoids.
Most cases are related to 21-hydroxylase or 11-ß hydroxylase deficiency. Ninety percent of cases of congenital adrenal hyperplasia are the result of a deficiency of the enzyme 21-hydroxylase. Deficiency of 11-ß hydroxylase is found in 8 to 9 percent of patients with congenital adrenal hyperplasia
Classic Congenital Adrenal Hyperplasia
Data from several neonatal screening programmes show that CAH due to 21-hydroxylase deficiency is common.
Data from roughly 6·5 million newborn infants screened in 13 countries (USA, France, Italy, New Zealand, Japan, UK, Brazil, Switzerland, Sweden, Germany, Portugal, Canada, and Spain) show an overall incidence of one in 15 000 livebirths for the classic form.
incidence varies according to ethnicity and geographical area. The highest rates of classic CAH occur in two geographically isolated populations: the Yupic Eskimos of Alaska (one in 280) and the French island of La Réunion (one in 2100). High rates have also been reported in Brazil (one in 7500) and the Philippines (one in 7000). In the USA, the incidence of CAH is lower in African-Americans than in the white population (one in 42 000 vs 15 500).
Non classic Congenital Adrenal Hyperplasia
However, non-classic CAH is estimated to be more common than classic CAH, with a prevalence of one in 1000 in the white population. A study in New York City found that non-classic CAH is more frequent in certain ethnic populations, such as Jews of eastern European origin, Hispanics, and Yugoslavs
Contributed by Lawrence Oh
Reference:
http://www.sciencedirect.com.ezproxy.lib.monash.edu.au/science?_ob=ArticleURL&_udi=B6T1B-4GDK8Y6-10&_user=542840&_coverDate=06%2F24%2F2005&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000027659&_version=1&_urlVersion=0&_userid=542840&md5=5a107fbfbaf3350499b07bb3784f894a
http://www.aafp.org/afp/990301ap/1190.html
1.Classic Congenital Adrenal Hyperplasia
- the more severe form of the disease affecting very young children
2.Non-classic congenital adrenal hyperplasia
- a milder form that usually develops in late childhood or early adulthood.
Both classic and nonclassic forms of the disease are caused by deficiencies in the adrenal enzymes that are used to synthesize glucocorticoids.
Most cases are related to 21-hydroxylase or 11-ß hydroxylase deficiency. Ninety percent of cases of congenital adrenal hyperplasia are the result of a deficiency of the enzyme 21-hydroxylase. Deficiency of 11-ß hydroxylase is found in 8 to 9 percent of patients with congenital adrenal hyperplasia
Classic Congenital Adrenal Hyperplasia
Data from several neonatal screening programmes show that CAH due to 21-hydroxylase deficiency is common.
Data from roughly 6·5 million newborn infants screened in 13 countries (USA, France, Italy, New Zealand, Japan, UK, Brazil, Switzerland, Sweden, Germany, Portugal, Canada, and Spain) show an overall incidence of one in 15 000 livebirths for the classic form.
incidence varies according to ethnicity and geographical area. The highest rates of classic CAH occur in two geographically isolated populations: the Yupic Eskimos of Alaska (one in 280) and the French island of La Réunion (one in 2100). High rates have also been reported in Brazil (one in 7500) and the Philippines (one in 7000). In the USA, the incidence of CAH is lower in African-Americans than in the white population (one in 42 000 vs 15 500).
Non classic Congenital Adrenal Hyperplasia
However, non-classic CAH is estimated to be more common than classic CAH, with a prevalence of one in 1000 in the white population. A study in New York City found that non-classic CAH is more frequent in certain ethnic populations, such as Jews of eastern European origin, Hispanics, and Yugoslavs
Contributed by Lawrence Oh
Reference:
http://www.sciencedirect.com.ezproxy.lib.monash.edu.au/science?_ob=ArticleURL&_udi=B6T1B-4GDK8Y6-10&_user=542840&_coverDate=06%2F24%2F2005&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000027659&_version=1&_urlVersion=0&_userid=542840&md5=5a107fbfbaf3350499b07bb3784f894a
http://www.aafp.org/afp/990301ap/1190.html
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