Ever wonder why some people get mono and others don’t? Almost 95% of adults carry antibodies to the Epstein Barr virus that causes mono, but less than 30% of people are estimated to get mono. [CDC.gov] Turns out that there may be a genetic susceptibility to mono as well as environmental factors. Twin studies, one way of determining heritability of a condition, show that identical twins are twice as likely to both have mono as fraternal twin siblings. [ref]
There aren’t a lot of studies seeking to determine exactly where the genetic susceptibility of a person to mono lies. My guess is that there isn’t any money in knowing that answer, but as a parent of a teen who has been exposed, I would like to know if he will get it!
A 2007 study with approximately 200 participants determined that certain HLA polymorphisms “may predispose patients to development of IM [infectious mononucleosis] upon primary EBV [Epstein Barr virus] infection.” The study found that for rs253088, the A/A genotype was less frequent in the infectious mononucleosis group. It also found that for rs6457110 the T allele was found less frequently in the mono group. [ref]
A 2001 study found that for the IL10 gene, a haplotype of A/TA (TA/T in 23and me orientation) on rs1880896, rs1800871, and rs1800872 is protective against Epstein Barr infection. [ref]
More studies have been done on the link between having had mono and later developing multiple sclerosis. HLA-DRB1*1501 serotype is highly correlated with the rs3135388 T-allele of HLA-DRA. Studies have found that those with the HLA-DRB1*1501 (look at rs3135388 T allele) are at a higher risk of multiple sclerosis, especially if they have had mono. [ref]
If you have mononucleosis, there is a 2014 study showing that high doses of vitamin C may help shorten the duration of the disease. [ref]