Lupus is not a genetic disease but you and your sister might have the same set of genes that make your immune system vulnerable to a trigger. I have MCTD and so does my younger sister. MCTD is quite rare but it would be wrong to conclude that it is a true genetic disease. It is not based on the best understanding science has. No one else in our family ever had any auto immune disease and my sister is much younger. I was out of the house by the time she was a toddler.
Studies of various AI diseases show that they tend to run in families although not everyone gets the same disease...but they all get some kind of AI disease.
My kids have my genes and those from my ex wife where MS runs in the family. My oldest son who is 42 just was tested for MS but they do not think he has it. Hopefully neither of my biological sons will have a problem but they definitely have a gene set that could go haywire some day.
Mixed connective tissue disease (systemic lupus, scleroderma, polymyositis), Raynauds phenomena, Hypertension, Barrett's syndrome.
Meds: prednisone (9mg & tapering), 150mg imuran, lisinopril 40mg, maxide 37.5/25mg, norvasc 5 mg, folic acid, potassium, aciphex 20mg, multi vitamins.
Maintain your optimism and you can beat the odds.
"Although the world is full of suffering, it is also full of the overcoming of it." Helen Keller