A 10-year-old boy presents with carpopedal spasm and perioral numbness. Laboratory results show calcium 6.8 mg/dL, phosphorus 7.2 mg/dL, intact PTH 185 pg/mL (elevated), and normal 25-hydroxyvitamin D. He has short stature, round face, short 4th and 5th metacarpals, and subcutaneous ossifications on examination. What is the diagnosis?

• A Pseudohypoparathyroidism type 1a ✓
• B Primary hypoparathyroidism
• C Chronic kidney disease stage 3
• D Severe vitamin D deficiency

Explanation

Pseudohypoparathyroidism type 1a (Albright hereditary osteodystrophy) features end-organ resistance to PTH causing hypocalcemia and hyperphosphatemia despite elevated PTH. The phenotype includes short stature, round face, shortened 4th and 5th metacarpals, and subcutaneous ossifications. Primary hypoparathyroidism would have low PTH without skeletal features.

Reference: Williams Textbook of Endocrinology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.