Parkinsonism is a group of neurological diseases with symptoms including bradykinesia, muscle stiffness, resting tremor, and postural instability. Parkinson’s disease, the most common form of parkinsonism and the second most frequent neurodegenerative disease (after Alzheimer’s disease), is clinically characterized by these four cardinal motor symptoms, as well as by a good response to treatment with levodopa.
Its prevalence is estimated to be between 1%-2% of the population at age 65 and about 4% at age 85. Approximately 15% of cases are familial, although some studies suggest that up to 60% of sporadic cases could be explained by genetic factors (Hamza et al., 2010). It is currently considered a multifactorial disease, with numerous environmental and genetic factors involved.
The most commonly involved monogenic determinants have been selected for a core study panel for this disease, including SNCA, LRRK2, and VPS35 (with autosomal dominant transmission and generally late onset), and PRKN (PARK2), PINK1, and PARK7 (DJ1) (with autosomal recessive transmission and an earlier onset).
For the study of early-onset parkinsonism, usually appearing during adolescence (<20 years), we have developed a specific panel with the most common causative genes.
Other types of atypical parkinsonism and Parkinson-plus disorders (such as progressive supranuclear palsy, corticobasal degeneration, multiple system atrophy, or Lewy body dementia) are covered by the comprehensive panel.