GH1 and celiac disease: After excluding other causes of poor growth, including hypothyroidism, celiac disease, and adrenal insufficiency, the patient underwent growth hormone stimulation testing using clonidine and arginine after priming with estrogen (2 mg nightly for 2 consecutive nights preceding stimulation test), which showed subnormal peak growth hormone levels of 1.2, 4.5, 4.4, 1.6, 0.7, 2.2, 4.6, 3.4 ng/mL (SI: 1.2, 4.5, 4.4, 1.6, 0.7, 2.2, 4.6, 3.4 μg/L) (reference range, > 6 ng/mL [SI: > 6 μg/L]).