I’m fortunate enough to have nothing but dust and pollen allergies. But my wife died from a compromised immune system that impacted her bone marrow. Both my kids inherited her immune system. One has all kinds of food allergies. The other has psoriatic arthritis and bowel disorders. I feel for both of you.
Ears perked up when you said psoriatic arthritis. HLA-B27 (the gene variant I mentioned earlier with my family history) has a med school nickname Mnemonic / Memory device called PAIR. (Psoriasis, Ankylosing spondylitis, Inflammatory bowel disease, and Reactive arthritis.)
I have the AS as do other family members. Plus as I mentioned earlier many of my family members and myself have various digestive system / autoimmune inflammatory bowel disorders.
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That said (not an expert for what I am about to say) psoriasis and psoriatic arthritis is a complicated genetic thing where they identified dozens of genes involved with it.
HLA-B27 is common in some variants of Psoriatic Arthritis with 40 to 50% of total cases having that gene variant.
Links to a 2017 New England Journal of Medical Review on it. (It is not important for you to read it.)
http://medicinainternaelsalvador.com/wp-content/uploads/2017/04/Psoriatic-Arthritis.pdf
But like I said before the genetics is complicated it is not just "one thing" ... but when you and several family members have AS (which has 90% of AS patients having HLA-B27) and then you have other problems caused by same genes, and other family members who do not have AS but have those other things that the gene can cause (PAIR after all), well you start to see one specific thing as a cursed gene even if in reality it is several hundred immune modulating genes working together as a team.
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I am tired, I had a long day and I decided to go out and get a peanut butter milkshake. I am apologizing for I am kind of rambling.
I am sorry Greg if you are reading this, both of you be safe as well as your family
