Chromogranin A Analysis in the Differential Diagnosis Across Lewy Body Disorders

Chromogranin A (CgA) is a general marker of gut endocrine cells, which are part of the "gut-brain axis" in Parkinson's disease (PD).

We analyzed CgA as a marker of synaptic dysfunction to assess its role in the differential diagnosis across different Lewy body disorders.

We analyzed the CgA levels in the cerebrospinal fluid (CSF) and serum from 54 patients covering the spectrum of Lewy body disorders [13 Parkinson's disease (PD), 17 Parkinson's disease dementia (PDD), 24 dementia with Lewy bodies (DLB)] and 14 controls using an ELISA.

A positive correlation was noted between CSF and serum CgA levels (ρ= 0.47, 95% CI: 0.24 to 0.65, p < 0.0001). The highest values of CgA in CSF and in serum were measured in DLB and there was a significant difference between DLB and PDD (p = 0.03 and p = 0.004). The serum levels of CgA in controls achieved lower values compared to DLB (p = 0.006). There was a gradual increase in serum levels from PD to PDD and DLB. An inverse correlation was seen between the CSF level of CgA and Aβ42 (ρ  = -0.296, 95% CI: -0.51 to -0.04, p = 0.02).

The incorporation of CgA analysis as an additional biomarker may be useful in the diagnostic work-up of Lewy body dementia. CgA analysis may be relevant in distinguishing DLB from PDD patients and presumably early stages of PD. Our data on altered serum levels in DLB pave the way to the development of blood-based parameters for the differential diagnosis, which however needs to be confirmed in a prospective study.