[Convulsive seizure].

A formerly healthy 14-year old boy with difficulties at school was admitted after two generalized seizures. Blood samples taken in the emergency room revealed normal serum-values for glucose and magnesium, but low calcium and elevated phosphorus. First evaluations showed normal age-related psychophysical development, serum-PTH was elevated and serum-1,25(OH)2D was normal. A CT-scan disclosed symmetric intracerebral calcifications. Further investigations confirmed the diagnosis of pseudohypoparathyroidism type 1B. Adequate treatment with calcium and calcitriol normalized serum-calcium, phosphorus and serum-PTH. Interestingly, school performance improved, as did personal activity.