Clinical and genetic study on 5 children with dopa-responsive dystonia due to tyrosine hydroxylase deficiency / 中华实用儿科临床杂志

ABSTRACT

Objective To explore the clinical characteristics,gene mutations,diagnosis and treatment of chil-dren with dopa-responsive dystonia due to tyrosine hydroxylase(TH)deficiency.Methods Five patients(3 boys and 2 girls)with dopa-responsive dystonia due to TH deficiency were diagnosed and followed up from January 2002 to October 2017.The clinical manifestations,laboratory findings,treatment and TH gene mutations associated with TH defi-ciency were analyzed.Results Five patients came from different families.They had the onset at the age of 8 months to 20 months with dystonia,paroxysmal muscular hypertonia and normal intelligence or mild mental retardation.All of them had been misdiagnosed as cerebral palsy.Two cases with floppy limbs presented with fatigue and tremor.One case with floppy limbs presented with seizures. Complex heterozygous mutations were found in TH gene of all patients,which helped to confirm the diagnosis.Eight mutations were identified in TH gene.Six of them were reported.Two novel muta-tions,c.1077C>A(p.C359X)and c.1228C>T(p.R410C)were detected.After the treatment by levodopa[2.2-5.4 mg/(kg·d)],significant improvement was observed.Three patients recovered their intellectual and motor activi-ties.Two patients were dramatically improved but with slightly uncoordinated movements.Conclusion The patients of dopa-responsive dystonia due to TH deficiency usually have the onset around one year of age with almost normal inte-lligence,motor retardation and dystonia.The patients are likely misdiagnosed as cerebral palsy.The treatment with levo-dopa can dramatically improve the symptoms.The etiological diagnosis is very important.