Clinical ObservationsEarly-Onset Parkinsonism: Case Report and Review of the Literature

BackgroundEarly-onset parkinsonism can be caused by PTEN-induced putative kinase 1 (PINK1) gene defects and is usually characterized by an age of onset in the fourth decade of life, slow disease progression, resting tremor, rigidity, bradykinesia, postural instability, and levodopa-induced dyskinesia.MethodsWe evaluated a child with early-onset symptoms and performed a literature review for previously reported examples of children aged 18 years or less with PINK1 gene defects.ResultsWe describe a five-year-old boy with autosomal recessive early-onset parkinsonism caused by a homozygous missense mutation in the PINK1 gene. This is the youngest individual yet reported with early-onset parkinsonism.ConclusionPINK1-type of early-onset parkinsonism can occur in very young patients, and phenotypic expression of PINK1 mutations may depend on age of onset and ethnicity.