[INTRODUCTION - Parathyroid hormone (PTH) excretion is increased both in primary hyperparathyroidism (pHPT) and in pseudohypoparathyroidism type Ia (PHP Ia). Pseudo-pseudohypoparathyroidism (P-PHP) is considered to be the normocalcemic form of pseudohypoparathyroidism type Ia. Our aim was to assess bone mineral content and bone quality as well as to determine whether these parameters are related to PTH levels in the above mentioned disorders. PATIENTS AND METHOD - 10 patients with pseudopseudohypoparathyroidism (P-PHP, age: 41.6 ±5.4 ys) were compared to 10 patients with primary hyperparathyroidism (pHPT) and to 10 healthy subjects, matched for age and gender. Moreover, nine patients with pseudohypoparathyroidism type Ia (PHP, age: 34.2 ±5.43 ys) were compared to nine age- and gender-matched patients with primary hyperparathyroidism and to nine healthy controls, respectively.The occurrence of previous bone fractures was recorded and bone mass was measured (by dual photon absorptiometry on the axial bones and by single photon absorptiometry on the forearm). Quantitative ultrasound (QUS) examination was performed both on the calcaneus by broadband ultrasound attenuation (BUA, dB/MHz) and speed of sound (SOS, m/s) measurements and on the proximal phalanges by amplitude-dependent speed of sound (AdSOS, m/s) measurements. In addition, some laboratory parameters of calcium metabolism were tested. RESULTS - No difference was found between PHP Ia and pHPT in bone mass.The lowest value was observed at the radius. Among the QUS parameters, pathologically low AdSOS was found at the phalanges in PHP Ia and it was lower than in pHPT patients, whereas at the calcaneus BUA showed a similar tendency. Bone mass did not significantly differ between P-PHP and healthy controls, it was decreased, however, at the forearm in the patients. Pathological AdSOS was found in P-PHP, which was lower than in pHPT. SOS at the calcaneus was lower in P-PHP than in pHPT, though it was not considered pathological. Laboratory results were typical for the diseases and the radiological examinations confirmed the diagnosis. Bone fractures occurred in three and two patients with PHP Ia and P-PHP, respectively, while no fractures were recorded in the pHPT and healthy groups. CONCLUSION - Bone loss among patients with PHP Ia is considered to be the impact of PTH excess on bone tissue.The deterioration of bone quality and architecture may play a role in the development of bone fractures.]
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