Objective:

Assess the presence of a synucleinopathy in autopsied conjugal couples.

Background:

Preclinical studies have shown that alpha-synuclein can spread through cell-to-cell-transmission, like prion disorders. Whether synuclein transmission occurs between humans is unknown. There have been few reported cases of conjugal Parkinson disease (PD) and multiple system atrophy (MSA), and none of dementia with Lewy bodies (DLB). It remains unclear if shared environmental exposure or transmission between spouses leads to conjugal synucleinopathies or whether it is chance alone.

Design/Methods:

Neuropathological findings of conjugal couples in the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND) were reviewed. All had annual movement and cognitive testing during life. Each spouse was then diagnosed as PD, DLB, Alzheimer’s disease with Lewy bodies (ADLB), incidental Lewy body disease (ILBD), or having no Lewy bodies.

Results:

Ninety conjugal couples (180 cases) were included, mean age of death 88.3±6.7 years. Thirty-two (35.6%) couples had no Lewy bodies. Forty-two (46.7%) couples had one spouse with a synucleinopathy: 10 with PD, 3 DLB, 13 ADLB, and 16 ILBD. There were 16 (17.8%) couples with both spouses having a synucleinopathy: 4 both had PD, 1 had PD and DLB, 4 had PD and ADLB, 2 had PD and ILBD, 1 had DLB and ADLB, 3 had ADLB in both spouses, and 1 had ADLB and ILBD. No couples both had ILBD. No MSA cases were found. The overall prevalence of PD was 25/180 (13.9%), DLB 5/180 (2.8%), ADLB 25/180 (13.9%), and ILBD 19/109 (17.4%). There was no difference in mean age of death between couple groups with a synucleinopathy.

Conclusions:

This large series of 90 autopsied conjugal couples only found 16 conjugal couples with synucleinopathies. Both spouses having PD, or PD and DLB was rare, suggesting transmission of synucleinopathy between spouses is unlikely.