Calcium-phosphate metabolism in autosomal recessive idiopathic strio-pallido-dentate calcinosis and Cockayne's syndrome.

In three siblings with autosomal recessive idiopathic strio-pallido-dentate calcinosis (SPDC) and in three other siblings with Cockayne's syndrome (CS) studies on plasma values of calcium and phosphate, intestinal calcium absorption, radiograms of the hands and studies on the influence of parathyroid hormone (PTH) on the renal threshold for phosphate revealed no abnormalities. In one of the SPDC patients and one of the CS patients the effect of PTH on the cyclic adenosine monophosphate (cAMP) concentrations in urine and cerebrospinal fluid (CSF) were determined. In both a normal response of urinary cAMP was noted. In the CS patient the response of CSF cAMP was also normal. The SPDC patient, however, had a significantly decreased response of CSF cAMP. It is suggested that a decreased sensitivity of the cerebral adenylate cyclase complex is involved in the etiology of autosomal recessive idiopathic SPDC. Subsequently this disorder could be considered as cerebral pseudohypoparathyroidism. The etiology of CS remains unknown.