I went on a deep dive into medical papers about RSI and related topics and here is what I found:
Tendon and Ligament Regeneration and Repair: Clinical Relevance and Developmental Paradigm states that tendoin healing responses are generally weak and make treatment of tendoin injuries difficult. A certain protein “Scleraxis”, a building block for tendoin tissue, is not sufficiently produced.
Mutations in COMP cause familial carpal tunnel syndrome finds that a mutation of the “catilage oligomeric matrix protein” (COMP), often found in Carpal tunnel syndrome patients, can cause inability of this proteins job: folding a certain protein into a ring of this protein. If the folding doesn’t succeed, a residue is left in the “endoplasmatic reticulum” (ER), the general protein soup in a cell. If too many unfolded proteins reside in a cell, the body triggers a so called “Unfolded protein response”, a type of inflamation. Wikipedia mentions that this response can be reduced or improved with Omega-3 fatty acids (Chiaseeds, Walnuts, Fish, …) and Ginger.
Current Progress in Tendon and Ligament Tissue Engineering describes the healing process of tendoins in “Tendon/ligament repair and healing”. Healed tendon has poor biochemical and mechanical properties compared to normal tendon tissue, even less than 50% of quality in many properties.
This last one goes down the rabbithole: Apoptosis is the process of “falling leaves” in the body. A programmed intentional death of cells, e.g. due to malfunction or being in some way comprimised, wheter due to mutated DNA or otherwise. To avoid these cells replicating, they are killed off (are their remains recyled?). TGF-beta-3 is linked to increasing Apoptosis by Dietary fiber enhances TGF-β signaling and growth inhibition in the gut. Inhibited apoptosis is linked to cancer and inflamation, so maybe a inhibited regeneration of cells.
Assuming apoptosis is a desireable process, we could be able to stimulate it through intake of dietary fibers: wholewheat anything, fruit (entire thing, not the juice, that is without fiber), brokkoli, carrots, peas, beans, potatoes with skin and nuts and seeds.
Sugar intake from fruit can also be defused by simultaneous intake of fiber (i.e. fruit vs fruit juice), as stated in WHY Sugar is as Bad as Alcohol (Fructose, The Liver Toxin).
Some Wilder Theories
These are pretty wild guesses, based on nothing but imagination! But feel free to investigate and let me know of your findings.
RSI might be caused by the genetic mutation, but also by repeated injuries in the tendons. The former can be improved by intake of ginger and omega 3, whereas the later appears more difficult.
The properties of new tissue might explain a repeated injury/chronicness of the disease: new tissue could be more prone to injury.
During this research I found a disbalance in diet compared to our prehistoric diets. This might lead to a difficiency of building blocks/resources for certain healing processes or causing sort of “plan b” provisory healing with suboptimal tissue.