The role of skin biopsy in differentiating idiopathic Parkinson's disease from other types of parkinsonism.

Abstract

Parkinson’s disease is one of the most common neurodegenerative disorders with a worldwide distribution. It has variable and complex phenotype with motor and non-motor manifestations, causes considerable psychosocial morbidity and consumes significant health care resources. Changing population demographics, and in particular, an ageing population in western societies is likely to result in gradually increasing prevalence. Despite significant advances in the understanding of disease pathology, the diagnosis of idiopathic Parkinson’s disease (IPD) remains largely clinical, with discriminatory investigations such as Ioflupane (123I)-labelled single-photon emission computed tomography (DaTSCAN) being used only in the minority of patients. However, postmortem studies have historically demonstrated the fallibility of relying on clinical phenotype and in differentiating IPD from ‘Parkinson’s plus’ conditions such as multiple system atrophy (MSA). An in vivo accessible peripheral biomarker for IPD and MSA would, therefore, be of great value to direct therapy and more accurate patient counselling. The three papers discussed below assess the value of one of the most promising of the available candidate biomarkers in this context; phosphorylated alpha-synuclein (p-α-Syn) which has recently been identified within dermal nerve fibres in IPD. In the first paper, the authors examine the utility of p-α-Syn as a biomarker for diagnosis of IPD, the second looks at p-α-Syn as a biomarker for MSA and the third at using p-α-Syn to differentiate IPD from MSA.