Table 4

Some reported possible biomarkers in the early diagnosis of PD

Biochemical/histopathology markers
 Rectal/colonic biopsyPhosphorylated α-synuclein-positive Lewy neurites; α-synuclein-positive nerve fibres (figure 1)
 Skin biopsyα-Synuclein accumulation
 Gastric biopsyPhosphorylated α-synuclein-positive Lewy neurites
 Low uric acidProposed
 Low-density lipoprotein/serum cholesterolProposed
Genetic markers
 Leucine-rich repeat kinase 2 mutation (G2019S)
 Glucocerebrosidase mutation
Imaging markers
 Transcranial sonography
 DAT scan
 The above two can be used in conjunction with clinical symptoms such as hyposmia or REM sleep behaviour disorder
Clinical markers combined with imaging
 NMSQuest, SCOPA AUT, smell-identification test (figure 2) and transcranial sonography—can be used as marker with 95.8% sensitivity in PD7
  • PD, Parkinson's disease; NMSQ, Non-Motor Symptoms Questionnaire; SCOPA AUT, SCOPA autonomic scale.