Hypoparathyroidism and facial dysmorphism as main symptoms of 22q.11 deletion syndrome

A 12-year-old Japanese boy with mental retardation and facial dysmorphism developed frequent convulsions, and hypocalcemia due to hypoparathyroidism was recognized. Chromosomal analysis involving the fluorescence in situ hybridization method revealed a microdeletion of 22q11.2. However, other laboratory examinations revealed no cardiac anomaly, thymic hypoplasia, or cleft palate. It is well known that typical cases of 22q11 deletion syndrome have a cardiac anomaly, thymic hypoplasia and a cleft palate. However, the phenotype of 22q11 deletion syndrome is diverse, and hypoparathyroidism and facial dysmorphism have been reported in nine cases, including this case, associated with 22q11 deletion. This combination of clinical manifestations could be given another term, such as hypoparathyroidism-facial syndrome. Some hypoparathyroidism patients due to 22q11.2 deletion may be misdiagnosed as having idiopathic hypoparathyroidism, and a child diagnosed as having hypoparathyroidism should be examined for chromosomal 22q.11.2. deletion