Evaluation of age of death in Niemann-Pick disease, type C: Utility of disease support group websites to understand natural history.

Niemann-Pick disease, type C (NPC) is a neurodegenerative lysosomal storage disease affecting the visceral organs and the central nervous system. The age of initial presentation varies from fetal to adult onset, although childhood onset is most common. The life expectancy for the full spectrum of NPC patients is not well defined, and it is unknown if current supportive care impacts the natural history. In order to assess age of death for a large cohort of NPC patients, we "crowd-sourced" age and year of death from information posted on disease support group website memorial walls. We analyzed data from 338 individuals who died between 1968 and 2018. In addition to age of death, gender can be inferred from given names and photographs. The median age of death was 13 years with a range from 0.1-69 years. Although sex significantly affects survival of NPC1 mutant mice, we did not observe a gender dependent survival difference in NPC patients. Median age of survival across time increased between the earliest patients and the most recently deceased patient; however, we found no significant change in survival over the last 20 years. These data suggest that supportive medical care has not impacted survival in the recent past and provides support for the use of historic controls in evaluating therapeutic interventions.