title: Screening for dopa-responsive dystonia in patients with Scans Without Evidence of Dopaminergic Deficiency (SWEDD).
abstract: The clinical diagnosis of Parkinson's Disease (PD) is not supported by Single Photon Emission Computed Tomography (SPECT) using dopamine transporter radioligand in 4-15 % of patients. It has been hypothesized that this phenomenon, named "Scans Without Evidence of Dopaminergic Deficiency" (SWEDD), may be an adult-onset dystonia. We investigated the hypothesis that these patients might be affected by Dopa-Responsive Dystonia (DRD). We enrolled eleven unrelated patients (8 F and 3 M) with clinical parkinsonism and normal [(123)I]FP-CIT SPECT. The GTP-cyclohydrolase1 (GCH1) gene was sequenced in all patients; urine biopterin and neopterin analysis was carried out in nine and oral phenylalanine (Phe) loading in seven. Neurological examination showed bradykinesia and resting/postural tremor in all patients, and rigidity in ten, suggesting a clinical diagnosis of PD. We detected mild dystonic signs in eight cases. In particular, five of them presented cranial dyskinesias. No mutation of the GCH1 gene was found. The results of the urine biopterin and neopterin analysis and the oral Phe loading did not reveal biochemical abnormalities suggestive of reduced GCH1 activity. We confirm that some clinical features, namely the presence of focal or segmental dystonia, suggest an adult-onset dystonia in SWEDD cases. However, we exclude DRD caused by GCH1 gene mutations in the present series.
authors.affiliation: Department of Neurosciences and Reproductive and Odontostomatological Sciences, Federico II University, Via Pansini 5, 80131, Naples, Italy, anna_derosa@libero.it.
authors.forename: Anna
authors.initials: A
authors.lastname: De Rosa
authors.forename: Claudia
authors.initials: C
authors.lastname: Carducci
authors.forename: Carla
authors.initials: C
authors.lastname: Carducci
authors.forename: Silvio
authors.initials: S
authors.lastname: Peluso
authors.forename: Maria
authors.initials: M
authors.lastname: Lieto
authors.forename: Andrea
authors.initials: A
authors.lastname: Mazzella
authors.forename: Francesco
authors.initials: F
authors.lastname: Saccà
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Brescia Morra
authors.forename: Sabina
authors.initials: S
authors.lastname: Pappatà
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Leuzzi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: De Michele
mesh_terms: D000328:Adult; D000368:Aged; D020821:Dystonic Disorders / Q000175:diagnosis* / Q000235:genetics*; D005260:Female; D006136:GTP Cyclohydrolase / Q000235:genetics*; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D006136:GTP Cyclohydrolase