According to Dr. Sharon’s book, Survival of the Sickest, a hemochromatosis patient, Aran Gordon, experienced joint pain, heart flutters, and depression.
Is this a run-on sentence? If so, how can I correct it?
It's not a run-on sentence, but it is a bit awkward, comma-wise.
If it's clear that Dr. Sharon writes books, I think I'd eliminate the word book and then get rid of that comma. And unless the patient's name is important I'd eliminate it as well. If the name is vital, maybe it could go in a second sentence? And I'd drop the Oxford comma.
According to Dr. Sharon’s Survival of the Sickest, a hemochromatosis patient experienced joint pain, heart flutters and depression. The patient, Alan Gordon, got better after eating lots of chocolate.
ETA: Oxford comma optional, I guess. Kinda. A bit. Sort of optional. Maybe.
According to Dr. Sharon’s book, Survival of the Sickest, hemochromatosis patient Aran Gordon experienced joint pain, heart flutters, and depression.
Do you have to include the patient's name?
It's not a "run-on" -- I wish teachers wouldn't use that term, which makes students wary of writing long sentences. A "run-together" sentence is two independent clauses joined by a comma (sometimes called a comma splice). You're not in that territory with this sentence.
This is not a run-on sentence. A run-on sentence is when you combine several independent clauses with conjunctions or commas and just keep going and stringing thought after thought together without a break and you don't stop to put in a period but keep putting additional things that really should be separate sentences into the same sentence and so you have one big long sentence that really should be five or ten separate sentences and they're all just rammed together and the reader never gets to take a breath but the sentence just goes on and on and never seems to stop.
Not every long sentence is a run-on sentence. Perhaps more importantly, not every long sentence is bad. The problem is when a sentence becomes difficult to understand or digest. A list of three or four things doesn't make a sentence hard to understand. A list of a hundred things could get tedious, but even then, it's probably not hard to understand.