Peripheral neuropathy in Parkinson's disease.

Area of Science:

• Neurology
• Neuroscience
• Genetics

Background:

• Peripheral neuropathy (PN) is a nerve dysfunction increasingly recognized in Parkinson's disease (PD).
• This comorbidity exacerbates motor deficits in PD patients.
• Understanding the underlying mechanisms of PN in PD is crucial for patient care.

Purpose of the Study:

• To review the current evidence on the association between peripheral neuropathy and Parkinson's disease.
• To explore the underlying pathological mechanisms and genetic factors contributing to PN in PD.
• To discuss potential treatment strategies for PN in PD patients.

Main Methods:

• A comprehensive computer-based literature review was conducted.
• Utilized multiple peer-reviewed databases (e.g., Embase, PsycINFO, CINAHL).
• Focused on diagnostic criteria, underlying mechanisms, and treatment options for PN in PD.

Main Results:

• Evidence supports distinguishing large fiber neuropathy (LFN) from small fiber neuropathy (SFN).
• Links identified between prolonged L-DOPA, homocysteine (HCY), and methylmalonic acid (MMA).
• Potential causes include gene mutations (Parkin, MHTFR), mitochondrial disorders, and vitamin B12/cobalamin deficiencies.
• Accumulation of phosphorylated α-synuclein is a key feature requiring further study.

Conclusions:

• PN in PD is multifactorial, involving L-DOPA exposure, genetic predispositions, and nutritional deficiencies.
• Targeting vitamin B12 deficiencies and exploring COMT inhibitors are potential therapeutic avenues.
• Urgent need for robust randomized controlled and long-term cohort studies to investigate genetic mechanisms and novel treatments for PN in PD.