Parathyroid function and growth in 22q11.2 deletion syndrome.

Objective: To determine the frequency and expression of hypoparathyroidism and the factors of short stature in 22q11.2 deletion syndrome to optimize clinical care.

Study Design: Cross-sectional study of 39 patients 9.7 +/- 0.8 (2.5-20) years of age.

Results: The congenital abnormalities were cardiac defects in 33 of 39, thymus hypoplasia in 15 of 18 evaluated, and craniofacial dysmorphy in all; 15 patients (39%) had had one or more seizures. Before evaluation, 12 patients were hypocalcemic, with (n = 4) or without clinical manifestations, diagnosed before 1 month in 10 cases, at 3 months or 12 years in two others. At evaluation, 9 patients were hypocalcemic, 5 of 9 had been hypocalcemic, and 8 others had parathyroid hormone (PTH) concentrations low for their ionized calcium. One had high PTH without hypocalcemia and 2 were hypercalcemic. The values were below -2 SD at birth for weight and/or height in 26% of cases and at evaluation for height and body mass index in 23% and for insulin-like growth factor-I in 37%.

Conclusions: Parathyroid function was abnormal in 27 of 39 (69%) patients. This was not diagnosed in the majority. Short stature was probably due to intrauterine growth restriction, underweight, and growth hormone deficiency, as suggested by low insulin-like growth factor I.