Parkinson Disease Dementia

© 2016           

By Keith S. Wexler, MBA, Maternal Fetal Medicine, Prenatal Diagnosis and Biotech Consultant, GENASSIST, Inc.

Paul Wexler, M.D., F.A.C.O.G., Medical Director, GENASSIST, Inc.

Clinical Professor, Department of OB/GYN, University of Colorado Health Sciences Center

Clinical Professor, Division of Genetics/Dept. of Pediatrics, Univ. of Colorado/The Children’s Hospital



  • Dementia: A chronic or persistent disorder of the mental processes caused by brain disease or injury or marked by memory disorder, personality change or impaired reasoning.
  • Parkinson Disease: Progressive disorder affecting several areas of the brain specially substantia nigra which controls balance and movement.


  • 1-2% of the general population
  • 2-4% in 60 year olds or greater
  • If 1st degree relative with Parkinson Disease: Risk is 4-9% higher than the population risk.
  • 15-25% of Parkinson Disease is Familial.

Juvenile Onset Parkinson’s Disease: Onset before 20 years of age

Early Onset Parkinson’s Disease: Before 50 years of age

Regular Onset Parkinson’s Disease: Usually after 50 years of age

70% of patients with Parkinson Disease develop dementia. 

Mortality risk higher if dementia present.

Genes Involved in Autosomal Recessive Type Parkinson Disease:

  • PARK2 (PARKIN) (chromosome 6q25)
  • PARK7 (DJ1) (chromosome 1p36)
  • PINK1 (PARK6) (chromosome 1p36)
  • PARK9 (ATP13A2) (chromosome 1p36)

Other Genes Usually Involved in Autosomal Dominant Pattern of Inheritance:

  • PARK1 (chromosome 4q21)
  • PARK10 (chromosome 1p32)
  • PARK11 (chromosome 2q37)
  • PARK7 (DJ1) (chromosome 1p36 – ? early onset)
  • SNCA (chromosome 4q21)

Genes That Modify the Risk of Developing Parkinson Disease:

  • GBA (chromosome 1q21)
  • UCHL1 (chromosome 4p14)