AD GTP-Cyclohydrolase-1 Deficiency (Segawa Syndrome;DYT5a)- Case Report

MACHÁČEK, Martin, Patrícia MUŽLAYOVÁ, Ondřej HAVLÍN and Hana OŠLEJŠKOVÁ. AD GTP-Cyclohydrolase-1 Deficiency (Segawa Syndrome;DYT5a)- Case Report (AD GTP-Cyclohydrolase-1 Deficiency (Segawa Syndrome;DYT5a)- Case Repor). In 15th Congress of the European Pediatric Neurology Society (EPNS), Prague. 2023.

Basic information

• Original name: AD GTP-Cyclohydrolase-1 Deficiency (Segawa Syndrome;DYT5a)- Case Report
• Authors: MACHÁČEK, Martin, Patrícia MUŽLAYOVÁ, Ondřej HAVLÍN and Hana OŠLEJŠKOVÁ.
• Edition: 15th Congress of the European Pediatric Neurology Society (EPNS), Prague, 2023.

Other information

• Original language: English
• Type of outcome: Conference abstract
• Field of Study: 30209 Paediatrics
• Country of publisher: Czech Republic
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• Organization unit: Faculty of Medicine
• Keywords in English: Segawa Syndrome; Dopa Responsive Dystonia; DYT5a; L-DOPA; Tetrahydrobiopterin; GTP-Cyclohydrolase-1

Abstract

Case study: Objective: Autosomal dominant GTP-cyclohydrolase-1 deficiency (Segawa syndrome) is a rare inherited neurometabolic disease with an estimated incidence of 1:300 000. Segawa syndrome is caused by a pathological variant of gene GCH1 leading to insufficient production of tetrahydrobiopterin, which results in a lack of dopamine in the central nervous system. The disease manifests as a motoric developmental delay, early parkinsonism, and dystonia without significant cognitive impairment. The first clinical signs typically appear before six years of age. Patients show a dramatic and sustained improvement when treated with low-dose L-DOPA/carbidopa (DOPA-responsive dystonia). This report depicts a case of a recently diagnosed Segawa syndrome in a female pediatric patient who shows promising treatment results. The authors tend to familiarize health professionals with crucial aspects of Segawa syndrome. Methods: The authors describe a case of a female pediatric patient presenting with motoric development impairment, an early manifestation of extrapyramidal symptoms, without significant mental disability. The diagnosis remained unclear after a standard neurological and pediatric clinical and paraclinical examination. The authors considered DOPA-responsive dystonia and began an L-DOPA/carbidopa test (1 mg/kg/d) and genetic testing. Result: The L-DOPA/carbidopa test improved the patient's symptoms significantly and rapidly. Genetic testing revealed an autosomal dominant pathological variant in the GCH1 gene. The patient was diagnosed with Segawa syndrome. The girl remains in the authors' medical care and shows sustained improvement. Conclusions: Segawa syndrome is a rare neurometabolic disorder with an early manifestation and usually favorable prognosis. The authors suggest considering this disease in all children with motoric development impairment, early parkinsonism, and dystonia without significant cognitive impairment.