Jayne,

To answer your question! 17-hydroxyprogesterone (17-OHP) is one of the main parameters tested in a person with CAH to assess their level of control. 17-OHP is a ’steroid hormone’ produced in the cortisol pathway which builds up abnormally, behind the enzyme block, in patients with the 21-hydroxylase deficiency type of CAH. It’s like the 17-OHP can’t get through to make the required cortisol, because of the block in the pathway. This 17-OHP level rises moderately in non-classic CAH and more dramatically in classical CAH.

Although your son has ceased his medications, it probably would be a good idea for the doctors to keep an eye on his levels, eg. 17-OHP, androstenedione, testosterone etc. Although, your son may be well on his way to achieving his height goals, he will need to be aware that he may be prone to adrenal rest tissue in his testicles, if he remains untreated and his levels are elevated. It depends very much on the degree of severity of his CAH, so hopefully your doctor is overseeing this aspect.