Pseudopseudohypoparathyroidism with fibrous dysplasia

Area of Science:

• Endocrinology
• Genetics
• Radiology

Background:

• Pseudopseudohypoparathyroidism (PPPD) and pseudohypoparathyroidism (PHP) are considered variants of Albright hereditary osteodystrophy (AHO).
• PPPD is characterized by features of AHO but normal serum calcium and phosphate levels.
• The Albright dimpling sign, resulting from underdeveloped metacarpal and metatarsal heads, is a key diagnostic indicator.

Purpose of the Study:

• To present a case study of a patient with pseudopseudohypoparathyroidism.
• To highlight the diagnostic utility of the Albright dimpling sign.
• To report an unusual association of fibrous dysplasia in the mandible with a hypoparathyroidism variant.

Main Methods:

• Clinical examination and assessment of characteristic features of PPPD.
• Radiographic evaluation of metacarpal and metatarsal bone development.
• Biochemical testing, including parathyroid hormone infusion response and urinary cyclic AMP excretion.
• Histopathological examination (light and electron microscopy) of mandibular tissue.

Main Results:

• The patient exhibited classic PPPD features, including shortened metacarpals/metatarsals and round facies, with normal serum calcium.
• The Albright dimpling sign was present and contributed to the diagnosis.
• The patient showed a normal parathyroid hormone response with increased urinary adenosine 3',5' cyclic monophosphate.
• Mandibular studies revealed fibrous dysplasia, a finding not previously reported in association with hypoparathyroidism variants.

Conclusions:

• The Albright dimpling sign is a valuable clinical marker for diagnosing pseudopseudohypoparathyroidism.
• This case expands the known clinical spectrum of Albright hereditary osteodystrophy variants.
• The co-occurrence of fibrous dysplasia in the mandible with PPPD represents a novel finding requiring further investigation.