What Do Treatments For Accelerated Aging Tell Us About Normal Aging?

https://astralcodexten.substack.com/p/what-do-treatments-for-accelerated

Progeria is a rare disease that makes people age unnaturally quickly. Babies born with progeria can lose their hair in toddlerhood, get wrinkles by grade school age, and die - apparently of old age - in their early teens. You can see a picture of a progeroid child here, though I don't recommend it.

There's been a lot of research on one important form - Hutchinson-Gilford Syndrome - and just last year, the FDA approved the first treatment, a drug called lornafarnib. In the study, a few hundred children averaging around 7 years old took the drug for two years; 3% died during that time. In an ad hoc group of untreated comparison children, about 30% died during the same period. I'm a little confused by the methodology - it seems like the "comparison children" were chosen partly because they died too early to get into the trial, which sounds like a pretty major confounder - but everyone seems to treat this as reasonable so I will assume they adjusted for this in some way. If that's true, then lornafarnib cuts mortality by 90%.

That's great for the 300 or so children worldwide with Hutchinson-Gilford progeria (it's a really rare disease). But none of the discussion about this answered the question I wanted to know: can lornafarnib also prevent normal aging?

After looking into this more, I find some evidence the the answer is no, but also some reasons why maybe it's less clear cut than that?

Hutchinson-Gilford progeria (I'll just say "progeria" from here on, even though that's kind of inaccurate) is what's called a laminopathy. It's a disease of the nuclear lamina, a weblike structure that helps support and give shape to the cell nucleus. The lamina is partly made of a protein called lamin A. Children with progeria have a mutation in the relevant gene; instead of producing lamin A, they produce a defective mutant protein called progerin. The cell tries to build the nuclear lamina out of defective progerin instead of normal lamin A, and as a result the cell nucleus is screwed up and can't maintain a normal shape.