Skip to main content


Table 2 Characteristics of included studies for assessment of association between genetic variants and LR in PD

From: A systematic review and integrative approach to decode the common molecular link between levodopa response and Parkinson’s disease

Study Population/Ethnicity Response criteria Agea (years) Gender Number of samples Genes Studied variants p-value OR (95% CI) Dosea (Drug) Treatment length (year) Score
M F Total R NR
Tan EK et al. [48] Singapore UPDRS 69.9±7.6 24 15 39 NA NA COMT rs4680 0.004 - 7.37 mg/ week (P); 421.5  ± 226.2mg (L) at least 3 months 12
Liu YZ et al. [51] Chinese UPDRS-I, HY <2.5 61.90  ± 8.20 14 16 30 11 19 DRD3 rs6280 (Ser/Ser) 0.024 9.75( 1.60- 59.70) * 0.125mg/thrice a day (L, B,P) > 3 months 12
Devos D et al. [52] Caucasian UPDRS-III, HY >30 23 10 33 14 19 DDC rs921451 0.048 - NA (L,B) NA 13
8 25 rs3837091
Moreau C et al. [54] French UPDRS II, III 60-63 NA NA 61 NA NA SLC6A3 rs28363170 0.005 - 710  ± 90.8mg/day (L) 16-17 12
rs3836790 <0.001 -
  1. M male, F female, R responder, NR non-responder, bp base pair; Dose of drug are in mg/day. Unit of Age, Dose and Follow up period are represented with Mean  ± standard deviation; a unit of age and dose are represented with Mean ± standard deviation; OR, Odds Ratio; *OR calculated using reported frequencies from the respective article; UPDRS Unified Parkinson’s disease rating scale, HY Hoehn and Yahr Staging of Parkinson's Disease; Drugs are L-levodopa, C-carbidopa, A-amantadine, T-, DA-Dopamine Agonist, MBI-MAO-B inhibitor, S-Selegiline, R-Ropinirole, E-Entacapone, P-Pramipexole; PCR-RFLP, Polymerase chain reaction- Restriction fragment length polymorphism. NA No Association; -,Insufficient data. Bold are significant polymorphisms (p≤ 0.05) and their corresponding genes