Contribution of testosterone and estradiol in sexual dimorphism of early-onset Parkinson's disease

Early-onset Parkinson's disease (EOPD) occurs during the fertile life, when circulating neuroactive sex hormones might enhance the sexual dimorphism of the disease. Here, we aimed to examine how sex hormones can contribute to sex differences in EOPD patients. A cohort of 34 EOPD patients, 20 males and 14 females, underwent comprehensive clinical evaluation of motor and non-motor disturbances. Blood levels of estradiol, total testosterone, follicle-stimulating hormone, and luteinizing hormone were measured in all patients and correlated to clinical features. We found that female patients exhibited greater non-motor symptoms and a relatively higher rate of dystonia than males. In females, lower estradiol levels accounted for higher MDS-UPDRS-II and III scores and more frequent motor complications, while lower testosterone levels were associated with a major occurrence of dystonia. In male patients, no significant correlations emerged. In conclusion, this study highlighted the relevance of sex hormone levels in the sexual dimorphism and unique phenotype of EOPD.