4 ms·

I find it really curious that evolution didn't get rid of such nasty condition. Too much sugar you die, too much insulin you die. And that affects you since b

I find it really curious that evolution didn't get rid of such nasty condition. Too much sugar you die, too much insulin you die. And that affects you since birth. How is it possible that something so deadly (that I assume is genetic) still exists?

alex_stoddard 5y ago
It's an auto-immune disease with complex causality. It doesn't necessarily manifest at birth, the time to develop the auto-immune response and for it to become severe varies. For some individuals perhaps it never develops. The same propensity to develop a harmful (until my mother's generation invariably fatal) immune response attacking the body's own insulin producing cells might be an advantage to fighting off certain infections (possibly in a different genetic context or living with a different set of environmental exposures).
ray__ 5y ago
It isn't (entirely) genetic. There are some genes that are risk factors, but no one knows what causes T1D. It also doesn't affect you at birth–it's an autoimmune disease that usually manifests between the ages of 3 and 20 but can appear at any time in life (see the other commenter in this thread whose wife developed T1D in her 40s). In keeping with this, the risk factor genes are mostly related to the immune system. Even in populations with the highest risk haplotype, only ~5% develop T1D, and many people without this haplotype also develop T1D. If it were purely genetic, evolution would have selected against these genes long ago since T1D was a terminal disease with a life expectancy of less than a year until the discovery and development of insulin-based therapies in the 1920s.
parrellel 5y ago
It's an autoimmune condition that needs to be triggered by "something" where something is thought to be some random unknown subset of mild childhood illnesses. Functionally, it means every generation or three you lose "a" kid at age 1 or 5 or 11, that isn't too much in the way of evolutionary pressure, especially given how many kids people used to have, and how many other ways there were for them to keel.

alex_stoddard 5y ago

It's an auto-immune disease with complex causality. It doesn't necessarily manifest at birth, the time to develop the auto-immune response and for it to become severe varies. For some individuals perhaps it never develops. The same propensity to develop a harmful (until my mother's generation invariably fatal) immune response attacking the body's own insulin producing cells might be an advantage to fighting off certain infections (possibly in a different genetic context or living with a different set of environmental exposures).

ray__ 5y ago

It isn't (entirely) genetic. There are some genes that are risk factors, but no one knows what causes T1D. It also doesn't affect you at birth–it's an autoimmune disease that usually manifests between the ages of 3 and 20 but can appear at any time in life (see the other commenter in this thread whose wife developed T1D in her 40s). In keeping with this, the risk factor genes are mostly related to the immune system. Even in populations with the highest risk haplotype, only ~5% develop T1D, and many people without this haplotype also develop T1D. If it were purely genetic, evolution would have selected against these genes long ago since T1D was a terminal disease with a life expectancy of less than a year until the discovery and development of insulin-based therapies in the 1920s.

parrellel 5y ago

It's an autoimmune condition that needs to be triggered by "something" where something is thought to be some random unknown subset of mild childhood illnesses. Functionally, it means every generation or three you lose "a" kid at age 1 or 5 or 11, that isn't too much in the way of evolutionary pressure, especially given how many kids people used to have, and how many other ways there were for them to keel.