Levodopa is effective in the treatment of three Chinese Tyrosine hydroxylase (TH) deficiency children.

• TH deficiency is an autosomal recessive inborn error of dopamine transmission, which the deficient gene is at the chromosome 11. • TH deficiency leads to developmental delay, infantile parkinsonism and encephalopathy. • We report three TH deficiency patients. After L-DOPA treatment, their condition had improvement. Tyrosine hydroxylase (TH) deficiency is a rare autosomal recessive inborn error of dopamine transmission, which the deficient gene is at the chromosome 11, also called'Segawa Syndrome'. TH converts tyrosine into L-DOPA, which is the direct precursor of catecholamine biosynthesis. TH deficiency causes a neurological disease with primary extrapyramidal signs and a variable response to L-DOPA. We report three patients in China who were diagnosed with Tyrosine hydroxylase (TH) deficiency by genetic testing and clinical manifestations. After L-DOPA treatment, their condition had sustained improvement. [ABSTRACT FROM AUTHOR]