Table 1.
Clinical, Biochemical, and Genetic Features of Pseudohypoparathyroidism and Related Disorders
| PHP1a | PPHP | PHP1b | PHP1c | PHP2 | POH | OC | |
|---|---|---|---|---|---|---|---|
| AHO manifestations | Yes | Yes | No* | Yes | No | No* | No |
| Serum calcium | ↓ | N | ↓ | ↓ | ↓ | N | N |
| Serum phosphate | ↑ | N | ↑ | ↑ | ↑ | N | N |
| Serum PTH | ↑ | N | ↑ | ↑ | ↑ | N | N |
| Other hormonal resistance | Yes | No | No* | Yes | No | No | No |
| Heterotopic ossification | Yes (superficial) | Yes (superficial) | No | Yes (superficial) | No | Yes (deep tissues) | Yes (superficial) |
| Response to PTH: | |||||||
| urinary cAMP | ↓ | ↑ | ↓ | ↓ | ↑ | ↑ | ? |
| urinary phosphate | ↓ | ↑ | ↓ | ↓ | ↓ | ↑ | ? |
| In vitro Gs-alpha activity | ↓ | ↓ | N | N | N | N or ↓ | ? |
| Inheritance | AD | AD | AD or Sporadic | AD | Sporadic | AD or Sporadic | AD or Sporadic |
| GNAS defect | Maternal inactivating mutations | Paternal inactivating mutations | Imprinting defects | Maternal inactivating mutations (rare) | None | Paternal inactivating mutations | Paternal inactivating mutations |
*
Except for some cases.
PHP, pseudohypoparathyroidism; PPHP, pseudopseudohypoparathyroidism; POH, progressive osseous heteroplasia; OC, osteoma cutis; AHO, Albright's hereditary osteodystrophy; PTH, parathyroid hormone; cAMP, cyclic adenosine monophosphate; GNAS, guanine nucleotide-binding protein, alpha-stimulating activity polypeptide; ↓, decreased; ↑, increased; N, normal; AD, autosomal dominant.