Prolactinoma as a cause of persistent hyperprolactinemia in 6-Pyruvoyl-tetrahydropterin synthase deficiency

Abstract

6-Pyruvoyl-tetrahydropterin synthase (PTPS) deficiency results in depletion of the brain neuro-transmitters serotonin and dopamine. Since dopamine is the physiological inhibitor of pituitary prolactin secretion, hyperprolactinemia is common in patients with PTPS deficiency. Serum prolactin concentrations are used for the monitoring and optimization of L-Dopa therapy. We report three adult patients with PTPS deficiency who had persistent hyperprolactinemia unresponsive to high dose L-Dopa therapy, and pituitary imaging confirmed microadenoma. In the presence of prolactinoma, serum prolactin is an unreliable tool for treatment monitoring in these patients. This report emphasizes the need to exclude other causes of hyperprolactinemia including prolactinoma, in patients who are compliant with optimized L-Dopa treatment and their prolactin levels remain significantly high.