[Significance of CSF biopterin and neopterin in hereditary progressive dystonia with marked diurnal fluctuation (HPD)--a clue to pathogenesis].

Hereditary progressive dystonia with marked diurnal fluctuation (HPD or dopa-responsive dystonia) is a clinical entity characterized by childhood-onset dystonia followed by parkinsonism, which shows dramatic response to levodopa. However, the same combination of the symptoms is also characteristic of some patients with juvenile parkinsonism (JP: manifesting below the age of 40), and sometimes the correct differentiation between these HPD and JP patients, in the early course of the disorder, may be difficult. In this study, therefore, we analyzed cerebrospinal fluid (CSF) biopterin (BP) and neopterin (NP) concentrations in 2 patients with HPD, 58 with idiopathic parkinsonism (IP: this group includes 25 cases with JP), 9 with dopa-nonresponsive dystonia (DNRD) and 18 controls, to search for biochemical differences among these disorders. Biopterin is the natural cofactor for tyrosine hydroxylase and NP consists of degradation products of dihydroneopterin triphosphate, which is the first intermediate in the BP biosynthesis from guanosine triphosphate (GTP). As a result, the mean BP level in the IP patients (8.5 +/- 0.3 pmol/ml; mean +/- SE) was significantly lower than those in both the controls (13.2 +/- 0.5, p < 0.001) and the DNRD patients (14.2 +/- 1.2, p < 0.001). The BP levels in the HPD patients (7.1, 5.9) were lower than the mean BP level in the IP patients. With regard to NP content, there were no significant differences in the mean NP levels among the controls (25.2 +/- 2.0 pmol/ml; mean +/- SE) and the patients with IP and DNRD (22.6 +/- 1.0, 25.2 +/- 2.2).(ABSTRACT TRUNCATED AT 250 WORDS)