High blood pressure in CAH usually occurs when there is too much salt or too much salt-retaining hormone. This can occur if you have 21-hydroxylase deficiency and are getting TOO MUCH salt or TOO MUCH Florinef. It can also occur if you have 11 hydroxylase deficiency and are getting TOO LITTLE glucocorticoid medication (hydrocortisone, prednisone, or dexamethasone.)

In a nutshell: Someone with 21-hydroxylase deficiency will naturally tend to LOSE salt. So, if the bp is too high, it usually means the medication doses are too HIGH. In contrast, someone with 11-hydroxlase deficiency will naturally tend to RETAIN salt. So, if the bp is too high, it usually means the medication doses are too LOW.

The best way to differentiate between 21-hydroxlase deficiency and 11-hydroxylase deficiency is by looking at, and analyzing, the levels of the different adrenal hormones. If you have 21-oh deficiency you will have high levels of the hormones "progesterone" and "17 hydroxyprogesterone." If you have 11-oh deficiency, you will have high levels of the hormones "deoxycorticosterone" and "11-deoxycortisol." With both these types of CAH, male hormone (androgen) levels are elevated.

DNA testing is helpful, once you are already pretty certain which type of CAH you have (e.g. 21-hydroxylase deficiency) and are just trying to track down the specific mutations. It is not really the right tool to use to when trying to differentiate between the different types of CAH (e.g. 21-oh and 11-oh deficiency).