Sporadic Pseudohypoparathyroidism Type Ib With TSH Resistance: Identification of Methylation Defects Within the GNAS Gene

摘要

An 18-year-old male was referred for evaluation of numbness of the limbs. Serum calcium levels were decreased and serum phosphate and parathyroid hormone levels were elevated. A parathyroid hormone stimulation test showed no increase in the urinary excretion of phosphate and cAMP. There was no family history of hypocalcemia or metabolic bone disease. The patient was diagnosed with sporadic pseudohypoparathyroidism. Gene analysis showed a loss-of-methylation defect in the GNAS 1 gene without a mutation of the Gsalpha gene. The patient is being treated with 1alpha-hydroxyvitamin D3, and the serum calcium level has remained normal since the time of diagnosis.