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[Cutaneous osteoma and Albright's hereditary osteodystrophy]
S Canillot1, B Chouvet, C Besançon
1Service de Dermatologie, Hôpital de l'Hôtel-Dieu, Lyon.
Annales De Dermatologie Et De Venereologie
|January 1, 1994
Summary
Albright's hereditary osteodystrophy, a genetic disorder, presents with varied symptoms including bone calcification. This case highlights pseudopseudohypoparathyroidism, a variant linked to G protein defects.
Area of Science:
- Endocrinology
- Genetics
- Skeletal Biology
Background:
- Albright's hereditary osteodystrophy (AHO) encompasses conditions with hormone resistance.
- Pseudohypoparathyroidism (PHP) and pseudopseudohypoparathyroidism (PPHP) are key AHO variants.
- Both PHP and PPHP involve defects in the G protein of adenylate cyclase.
Observation:
- A 35-year-old woman with AHO presented with recurrent auricular cutaneous ossifications.
- Clinical features included short stature, obesity, distinctive facial features, skeletal calcifications, cataracts, hearing impairment, and dental abnormalities.
- Normal serum calcium, phosphorus, and parathyroid hormone levels were noted.
Findings:
- Intravenous parathyroid hormone injection led to increased urinary phosphorus and cyclic adenosine monophosphate (cAMP) excretion, indicative of PPHP.
- This response suggests a defect in parathyroid hormone signaling via cAMP.
- AHO is associated with PHP (hormone resistance) or PPHP (no hormone resistance), considered variants of the same G protein defect.
Implications:
- The study underscores the clinical and biochemical variability of AHO and PHP.
- Understanding G protein signaling defects is crucial for diagnosing and managing AHO spectrum disorders.
- Current classification of PHP subtypes remains provisional due to expression variability.