cns disorder or diseases that run in families

does anyone know of disorders and or diseases that are genetic? It appears to be based on autoimmune disease or disorder (hypersensativity to infections) that result in cns/demylenating disorder/disease.
I started with overload of infections and lead to cns/demylenating disorder - see neuro  on Tues -hopefully has some answers although last time i saw him (6 months ago)  I  was not aware of cns/neuro involvement and my son recently started with infection battle (when he was younger had gone through 15 ear infectionns and found out he had neuro immune deficiency.
It seems odd that all three of us are following a very simular path. Cousins on my father's side have also battled the overload of infections.
Our paternal grandmother had poliarteritis nodosa, however I have been told that you can tell just by looking at a person whether they have this or not because of the effects on the skin. She passed away at 51.

Would reallly appreciate anybody's input or anything simular to this type of  family linked illness based on infections sensativity followed by cns/neuro implications.

sinceerely

mixedblessings