PSEUDOHYPOPARATHYROIDISM

Etiology:

• There is tissue resistance to the effects of PTH, so PTH concentrations are markedly elevated
• Type 1 a or Albright’s hereditary osteodystrophy (AHO) – GNAS1 mutation is inherited on the maternal chromosome

Clinical and histologic features:

• Hypocalcemia
• Hyperphosphatemia
• Short stature
• Short fourth/fifth metacarpals and metatarsals with associated Cataract
• Rounded face
• Obesity
• Subcutaneous calcification
• The response of urinary cAMP to PTH is decreased/normal and Heterotopic ossification may be characteristically seen.