These people represent the limit of human lifespan. For a variety of reasons not fully understood but including lifestyle choices, genetic variants, and chance, these individuals have escaped the usual causes of death including cancer, heart disease and stroke.
However, eventually they too die, with the world record holder being Jeanne Calment who survived until age 122.
In a newly published review Drs. Stephen Coles and Thomas Young of the UCLA Gerontology Research Group point out what it may be that is killing supercentenarians: amyloidosis.
Amyloidosis is a disease state hallmarked by the deposition of fibers of abnormally clumped masses of transthyretin. The protein transthyretin normally acts to carry thyroid and other hormones. Mutations in the gene make the fibers abnormally sticky and they tend to clump into long fibers which are deposited in multiple organs.
Through early onset amyloidosis leads to disease, it is of interests that supercentanarians all seem to have significant amounts of it. Though not proven it is possible the amyloid is killing them.
These persons have already escaped the typical causes of death however they have lived for so long, the normally innocuous amounts of amyloid that increase with age may actually become toxic to them because they have lived so many years.
Where this line of reasoning gets exciting is that experimental drugs exists which may eliminate amyloid.
These drugs are being studied for young persons with pathological amyloidosis. If they work, what would happen if they were adminstered to persons over age 95? Perhaps it is possible they could become the first drugs to extend human lifespan beyond current theoretical limits.