Pseudohypoparathyroidism with normal serum calcium level

Pseudohypoparathyroidism, parkinsonism syndrome, with no basal ganglia calcification

A 20 year old woman with pseudohypoparathyroidism, Parkinsonism and no basal ganglia calcifications shown by computed tomography is reported. She has typical features of pseudohypoparathyroidism and biochemical evidence of end-organ resistance to parathyroid hormone. She is mentally retarded and has tremor, rigidity, bradykinesia, and stooped posture. The cause of Parkinsonism in pseudohypoparathyroidism is thought to be basal ganglia calcification. This patient must have another pathophysiology, perhaps directly related to a G protein defect, causing impaired neurotransmission.

Secondary hyperparathyroidism with 1,25-dihydroxyvitamin D deficiency and pseudohypoparathyroidism in childhood: relationship between plasma 1,25-dihydroxyvitamin D and parathyroid hormone levels and urinary cyclic AMP response to exogenous PTH

In order to clarify the complex interrelationship between serum calcium, 1,25-dihydroxyvitamin D (1,25(OH)2D), and parathyroid hormone (PTH), and the urinary excretion of cyclic AMP (cAMP) in response to exogenous PTH in pseudohypoparathyroidism (PHP) and related diseases, we investigated 3 patients with parathyroid disorders before and after treatment with 1 alpha-hydroxyvitamin D3 (1 alpha-OH-D3). Low plasma 1,25(OH)2D before treatment increased after giving 1 alpha-OH-D3 (0.1 micrograms/kg/day), whereas high plasma PTH measured by the c-terminal assay (C-PTH) decreased in all 3. No response in urinary cAMP was found before or after treatment in 2 patients with PHP type I, despite the fall of plasma C-PTH. However, in one patient with extremely high plasma C-PTH but normal N-PTH (measured by a homologous radioimmunoassay using 1-34 human PTH), urinary cAMP response to exogenous PTH was increased after treatment with 1 alpha-OH-D3. We suggest that he had pseudopseudohypoparathyroidism (PPHP) with Albright's hereditary osteodystrophy and a partial deficiency of renal 1 alpha-hydroxylase. In this patient secondary hyperparathyroidism is thought to be due to 1,25(OH)2D deficiency, and the decreased responsiveness to exogenous PTH before treatment due to excess PTH occupying renal receptors.

Pseudohypoparathyroidism. Variable manifestations within a family

A wide variety of clinical and biochemical manifestations have been reported in association with pseudohypoparathyroidism and associated disorders. This is illustrated by a family study in which the affected members show widely differing characteristics.