Early manifestation of obesity and calcinosis cutis in infantile pseudohypoparathyroidism

Pseudohypoparathyroidism is a parathyroid hormone resistance condition, characterised by biochemical findings of hypocalcaemia or normocalcaemia with inappropriately elevated parathyroid hormone level and usually with a typical osteodystrophy feature. We report an infant with pseudohypoparathyroidism type Ia, who presented with obesity and calcinosis cutis as a clue to diagnosis. A 1-year-old female infant presented with suspected Cushing syndrome. She had round face, flushed cheeks, short nose and low nasal bridge. The infant was normotensive and not virilised. Investigations for Cushing syndrome were all negative. Calcinosis cutis was detected over both legs and the abdominal wall. Parathyroid hormone level was inappropriately elevated with a slightly high calcium level. Her mother was also noted to have Albright's hereditary osteodystrophy features with normal calcium and parathyroid hormone levels. Therefore, the diagnoses of infantile pseudohypoparathyroidism type Ia and maternal pseudopseudohypoparathyroidism were made. This infant presented with an early manifestation of Albright's hereditary osteodystrophy. Diagnosis of pseudohypoparathyroidism should be considered as an unusual cause of obesity in infants, particularly in the differential diagnosis of Cushing syndrome when tall stature rather than growth failure is present.