Objective: To study the clinical, pathological and genetic profile of Parkinson syndrome (PS) cases that have > 20 years survival (long survival, or LS) compared with those who have < 10 years survival (short survival, or SS) after clinical onset.

Background: PS is clinically diagnosed by presence of two of the three cardinal motor findings of bradykinesia, rigidity and resting tremor.  Prognosis and survival differences is based on onset ages, presence of dementia, and severity of motor symptoms at first assessment. The PS are distinguished by clinical/pathological findings. Progress in genetics have added genetic mutation as a factor in survival. One recent multicenter clinical study reported that survival in Parkinson disease (PD) of > 20 years is rare – 4% of patients.

Method: All patients were evaluated at the Saskatchewan Movement Disorders Program (SMDP) between 1968 and 2018.  Patients are followed longitudinally and offered autopsy at no cost.  One-half brain is studied by a certified neuropathologist, and the other half preserved at -80C. Genetic studies on frozen brain tissue were performed.  Autopsied PS cases that had > 20 years survival after onset were identified – all had onset before age 70. For comparison, we then identified all autopsied PS patients that had onset by age 70 but survived < 10 years.

Results: 445 PS cases came to autopsy between 1968 and 2018. The majority (80%) had Lewy body PD.  There were 58 (13%) long survival PS cases and 41 short survival PS cases.  At baseline visit to SMDP, 43% of LS cases were mild (Hoehn & Yahr Stage 1 and 2) and 9% were severe (H&Y 4 and 5).  By comparison, 42% of SS cases had mild and 24% severe disease at baseline visit.  Dementia was absent in 67% of LS and 73% of SS cases at baseline visit.  The vast majority (84%) of LS cases had PD as the final pathological diagnosis, while in the SS cases, the most common diagnosis was PSP (39%). The longest survival was seen in a small group of 5 benign tauopathy patients – 2 of those were sporadic and 3 had genetic mutations. Survival differences among the same pathological variants was linked to comorbidity.

Conclusion: Our data show that the type of pathology and genetic mutation are major determinants of survival in PS. Biological markers to determine the underlying pathology will be valuable in predicting the prognosis in PS patients.

References: This work was presented at the XXIV World Congress on Parkinson´s Disease and Related Disorders in Montreal, Canada, 16/06/2019-19/06/2019 but has not been previously published.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/long-and-short-survival-in-parkinson-syndrome-pathology-and-genetics-are-key-prognostic-factors/