17-HYDROXYPROGESTERONE RHYTHMS AND GROWTH VELOCITY IN CONGENITAL ADRENAL-HYPERPLASIA

Six patients on steroid replacement therapy for congenital adrenal hyp erplasia provided capillary blood samples collected at 0800, 1200, 170 0, and 2200 h, on to filter paper for 17-hydroxyprogesterone analysis. There was a strong correlation between 17-hydroxyprogesterone day pro files and height velocity over a 4 year period of study. Steroid over- replacement, identified by significantly decreased height velocity (St andard Deviation Score SDS! 1.92), caused suppression of 17-hydroxypr ogesterone concentrations to below 10 nmol/L throughout the day. Near average height velocity (Standard Deviation Score 0.245) was accompani ed by suppression of 17-hydroxyprogesterone concentrations below 40 nm ol/L but with significant diurnal variation. Under-replacement with ra pid height velocity and bone maturation was accompanied by non-suppres sion of 17-hydroxyprogesterone concentrations (i.e. >40 nmol/L). These results suggest that serial blood spot 17-hydroxyprogesterone measure ments are a convenient and helpful supplement to measurements of heigh t velocity and bone age maturation to monitor steroid replacement ther apy in congenital adrenal hyperplasia. These measurements may be usefu l particularly in differentiating between over-replacement and appropr iate replacement and should allow adjustments in dose before abnormal growth patterns are established.