Exploring determinants of progression in Parkinson's disease. Is there a difference among Jewish ethnic groups?

The impact of ethnicity on the clinical presentations of spinocerebellar ataxia type 3

BACKGROUND

For a variety of sporadic neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis, it is well-established that ethnicity does affect the disease phenotypes. However, how ethnicity contributes to the clinical symptoms and disease progressions in monogenetic disorders, such as spinocerebellar ataxia type 3 (SCA3), remains less studied.

METHODS

We used multivariable linear and logistical regression models in 257 molecularly-confirmed SCA3 patients (66 Caucasians, 43 African Americans, and 148 Asians [composed of 131 Chinese and 17 Asian Americans]) to explore the influence of ethnicity on age at onset (AAO), ataxia severity, and non-ataxia symptoms (i.e. depression, tremor, and dystonia).

RESULTS

We found that Asians had significantly later AAO, compared to Caucasians (β = 4.75, p = 0.000) and to African Americans (β = 6.64, p = 0.000) after adjusting for the pathological CAG repeat numbers in ATXN3. African Americans exhibited the most severe ataxia as compared to Caucasians (β = 3.81, p = 0.004) and Asians (β = 4.39, p = 0.001) after taking into consideration of the pathological CAG repeat numbers in ATXN3 and disease duration. Caucasians had a higher prevalence of depression than African Americans (β = 1.23, p = 0.040). Ethnicity had no influence on tremor or dystonia.

CONCLUSIONS

Ethnicity plays an important role in clinical presentations of SCA3 patients, which could merit further clinical studies and public health consideration. These results highlight the role of ethnicity in monogenetic, neurodegenerative disorders.

[Geriatric particularities of Parkinson's disease: Clinical and therapeutic aspects]

Parkinson's disease (PD) is a frequent and complex progressive neurological disorder that increases in incidence with age. Although historically PD has been characterized by the presence of progressive dopaminergic neuronal loss of the substantia nigra, the disease process also involves neurotransmitters other that dopamine and regions of the nervous system outside the basal ganglia. Its clinical presentation in elderly subjects differs from that in younger subjects, with more rapid progression, less frequent tremor, more pronounced axial signs, more frequent non-motor signs linked to concomitant degeneration of non-dopaminergic systems, and more frequent associated lesions. Despite the high prevalence of PD in elderly subjects, few therapeutic trials have been conducted in geriatric patients. Nevertheless, to improve functional disability while ensuring drug tolerance, the principles of optimized and multidisciplinary clinical management have to be known. The aim of this review is to provide an update on clinical and therapeutic features of PD specifically observed in elderly subjects.