Unmasking of Hypoparathyroidism in Familial Partial DiGeorge Syndrome by Challenge with Disodium Edetate

NEURAL-CREST cells participate in the embryonic development of the aortopulmonary and conotruncal septa and the thymus and parathyroid glands.¹ The recognition of a clinical syndrome with developmental anomalies of these tissues—the DiGeorge, or “third and fourth nasopharyngeal pouch,” syndrome — has suggested a causal relation for an abnormality of neural-crest development.² The clinical and pathologic manifestations of this syndrome are variable, ranging from the complete form, with absence of the affected glands and complex cardiac malformations (truncus arteriosus and interrupted aortic arch Type B), to less severe forms, with hypoplasia of the parathyroid glands and thymus, with or without an.