Linear Growth of Children With Congenital Adrenal Hyperplasia.

It has been reported that approximately one child in every 18000 born in Great Britain has CAH. In North America, the incidence varies from 1:15000 to 1:16000. The reported rates of CAH have been as high as 1:280 among the Yupik people of Alaska and 1:2100 on the French island of Réunion in Indian ocean; both of these populations are geographically isolated. The reported incidence of CAH in the two Brazilian states that have routinely included CAH in their public newborn screening programs is 1:11655 in the South (Santa Catarina) and 1:10325 in Midwest (Goiás).

Salt-losing CAH accounts for about three quartes of cases reported and non-salt losing CAH for one quarter. Non-classic is more common ;Estimated as 1 in 1000-2000 in white populations. It is more frequent in certain ethnic groups, such as the Ashkenazi Jewish population. The mild non-classic form is a common cause of hyperandrogenism.

Treatment of classic 21-OHD consists of replacement doses of gluco- (GC) and mineralocorticoids aiming to reduce excess androgen, and to allow adequate linear growth. However, several series report that growth in these children is below expectation, as compared with both the reference population and the target height (TH).

The reasons for the inadequate growth and impairment of the final height (FH) are not completely understood. A major cause is the difficulty in accomplishing a fine balance between inhibition of excess androgen production which accelerates bone maturation and adequate GC replacement itself which even at slightly supraphysiologic doses can be deleterious to growth.