title: Early-Onset Parkinsonism: Case Report and Review of the Literature.
abstract: Early-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.
  
  
  
  We 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.
  
  
  
  We 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.
  
  
  
  PINK1-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.
authors.affiliation: King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia; Neurology Division, Department of Pediatrics, King Abdulaziz Medical City, Riyadh, Saudi Arabia. Electronic address: rumayyana@ksau-hs.edu.sa.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Al-Rumayyan
authors.affiliation: Institute of Neurogenetics, University of Luebeck, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Klein
authors.affiliation: King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia; Genetics Division, Department of Pediatrics, King Abdulaziz Medical City, Riyadh, Saudi Arabia.
authors.forename: Majid
authors.initials: M
authors.lastname: Alfadhel
mesh_terms: D002675:Child, Preschool; D006720:Homozygote; D006801:Humans; D008297:Male; D020125:Mutation, Missense; D020734:Parkinsonian Disorders / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics* / Q000503:physiopathology; D011494:Protein Kinases / Q000235:genetics*; D000099202:PTEN-Induced Putative Kinase
chemical_list: D011494:Protein Kinases; D000099202:PTEN-Induced Putative Kinase
keywords: Parkinson disease; dystonia; early-onset parkinsonism; movement disorders; parkinsonism; pink1