Guanine triphosphate-cyclohydrolase 1-deficient dopa-responsive dystonia presenting as frequent falling in 2 children

Guanine triphosphate (GTP)-cyclohydrolase 1 (GCH1)-deficient dopa-responsive dystonia is caused by GCH1 gene mutation. Two children presenting with frequent daily falling are reported with GCH1 gene mutations with persistent response to low-dose levodopa/carbidopa. Typical and atypical clinical features associated with GCH1 mutations are also reviewed.