Ehlers-Danlos Syndrome
I'm fairly certain (99.9%) that I am affected by EDS (Classical Type). I once spoke to a dermatologist about it, and after a few questions1 he informed me that it's "nothing to worry about" because my symptoms were not terribly great. Further research on my part, however, revealed that he was only partly correct, which did not surprise me as he was an Army doctor and had previously, concerning another condition with which I am mildly afflicted, instructed me to "Google it" if I wanted more information2. The correct part of his prognosis is that the symptoms I display are not life-threatening (which, to the Army, meant unimportant), but it is certainly not "nothing to worry about." A sufficient or persistent force (lifting a heavy object or running long distances, for example) will subluxate my left shoulder or left hip, respectively, so I must be careful to not overexert these joints. Many of my joints are double-jointed and/or susceptible to subluxation, including wrists, elbows, hips, shoulders, thumbs, pinkies, and ankles. Also, I have moderate skin hyperextensibility, muscle hypotonia, and joint hypermobility, and I have at least one spheroid on my left forearm (feels like a BB under the skin).
Why should you care? Well, if you're related to me on my mother's side, there is a chance that you, too, are affected by Classical Type EDS because I'm fairly certain (again about 99.9%) that I inherited it from my maternal grandfather (it's autosomal dominant). Because the symptoms vary greatly in severity, you may have it and not notice, but double-jointed thumbs may be a good indicator. If you're interested in learning more, check out the links provided throughout this post or, in the words of perhaps the worlds greatest doctor, Google it. (Hey, at least I gave a link.)
1Doc: Can you touch the tip of your tounge to the tip of your nose?
Me: No.
Doc: Are you very flexible?
Me: Yes. *places foot behind head*
2Additionally, when I asked how to spell keratosis pilaris (I actually said, "How do you spell that?" because I could barely discern what he'd said), he seemed very agitated that I was so stupid. To that colonel who worked in dermatology at Madigan Army Medical Center in the fall of 2003 (who shall herein remain unnamed), I point out this web comic. Essentially, I mean that that doctor is a jackass.