I made a page listing the chromosomes and then the genes associated with each of them. I memorized the moderate to major disease gene-chromosome associations and also had some lower yield ones on the page just so that I would glance at them occasionally and be able to make a stab at them if I had to guess.
I also put some time into memorizing the lesser yield HLA associations (eg the ones other than B27) like Graves, Rheumatoid arthritis, MS, celiac disease etc...
This was all a waste of time, at least for my test. Needing to know the chromosome # for a gene did not come up on a single question, not even indirectly. The only HLA-disease association that came up had to do with reactive arthritis.
There are many topics that are easy for a specific test taker to look back and advise everyone not to study simply because it didn't show up in their test- but their test is just that. Yours is more likely to be different than it is to be very similar. That said, of the 5,000 prac questions I did and the actual, I really feel that chromosome-disease memorization is low low-yield. I would memorize the major ones just to be safe (BRCAs, p53, NF1/2, and maybe a couple others). I could be wrong.