Possibly twin chimerism?? Absorbed twin?

What's wrong with my sister? I’m wondering if my sister could possibly be a chimera…. She has a conglomerate of issues.

20F, 5'4", 135lbs, Caucasian. Primary complaint: Too many symptoms, too few answers.

Current medications: AS NEEDED: Imitrex–50mg, Ativan–1mg, Zofran–4mg. DAILY: Norco–5mg, Lyrica–75mg, Seroquel–100mg, Flexeril–10mg, Cymbalta–30mg, Cytomel–5mcg, Qulipta–60mg, Zyrtec–10mg.

Diagnoses: Hypothyroidism, Hypercholesterolemia, Chronic Idiopathic Urticaria, Tachycardia, Hypertrophic Cardiomyopathy of the Aortic Valve, Herniated Lumbar Discs (multiple), Chronic Migraines, Tilted Uterus, ADHD, OCD, PTSD, Severe Separation Anxiety, Generalized Depression.

Other Symptoms: Heart palpitations, chronically cold extremities, fatigue, extremely slow healing wounds, painful periods, hair thinning, brittle nails, random rashes/hives.

Surgeries: Jan 2020 Bilateral Breast Reduction (to help with back issues), Aug 2022: Microdiscectomy, Laminectomy of L5-S1 (torn ligament, bone spurs, herniated disc).

Testing: ANA screen was negative, TSH and T3 was normal, T4 was low, folate was normal, metabolic panel was all normal, rheumatoid factor was normal.

Based on her "research" aka Googling, she thinks she has a genetic mutation in the MTHFR gene or lupus.

I have some other ideas. She is a fraternal twin and our mother had lots of infertility treatments, hence the twins. Twins do not run in our family. They couldn't tell her gender for quite a while, as the ultrasounds were not clear enough. She was also born with a third nipple which she had removed during her breast reduction in 2020. I am suspicious of some sort of mosaicism, or twin chimerism. Upon some research (actual scientific journal research), I noted that although some people live perfectly normal lives with chimerism, it can also cause more serious health issues and can put one at a higher predisposition for autoimmune disorders. I am also interested in looking more into resistance to thyroid hormone syndrome, I want her A1C checked, and I want her HLA tested.

She asked me to go to the doctor with her tomorrow. If anyone has ANY ideas or things to look further into, or tell me if any of my ideas are crazy, please share. Please. I will take any help or advice I can get. She has been dealing with all of these health problems for so long and she is going down the depression hole because no one can tell her what is wrong with her. Thank you in advance. Cheers.