The Endocrine Manifestations and Growth of the Patients with 22q11.2 Microdeletion Syndrome

Lee, Jong Seung; Choi, Jin Ho; Yoo, Han Wook

Abstract

PURPOSE
Varying clinical phenotypes are associated with the chromosome 22q11.2 microdeletion syndrome. The endocrine manifestation are latent or overt hypoparathyroidism, thyroid dysfunction and short stature. This study was undertaken to investigate frequencies of endocrine abnormalities and short stature in patients with the chromosome 22q11.2 microdeletion syndrome.
METHODS
Forty three unrelated patients were diagnosed having chromosome 22q11.2 microdeletion syndrome. Chromosomal microdeletion was confirmed by fluorescent in situ hybridation (FISH) with DNA probe (22q11.2 LSI TUPLE1 from Vysis). Serum total calcium and intact parathyroid hormone (PTH) were measured in all patients. Thyroid function tests including free thyroxine(T4), thyroid stimulating hormone (TSH) and thyroid autoantibodies were performed in all patients. Insulin-like growth factor-1 (IGF-1) was measured in 10 patients. Height, weight and body mass index were compared with chronological age in all patients.
RESULTS
Seven patients (16%) had an overt hypoparathyroidism, presenting with hypocalcemic tetany. Thirteen patients (31%) showing hypocalcemia with normal PTH were regarded as having latent hypoparathyroidism since their PTH secretion response was blunted. Out of 2 patients with thyroid diseases, one patient had Graves disease and the other had Hashimoto thyroiditis. Five patients (12%) were below the 3rd percentile in height at evaluation. The BMI was below the 5th percentile in 23% of patients.
CONCLUSION
Twenty patients (47%) presented with overt and latent hypoparathyroidism. Interestingly, autoimmune thyroid diseases such as Graves disease and Hashimoto thyroiditis were associated in patients with chromosome 22q11.2 microdeletion, indicating predisposition to autoimmune disorders. Therefore, a careful endocrine and growth evaluation is needed in these patients.