Hi Michael,
Good to meet you.

Gosh, it's such a complex thing.

There are many, many different reasons why a person can have tics, plus Tourette's Syndrome is just a name for a particular cluster of symptoms for diagnostic purposes that shows it is different from some of the other Tic Disorders.

Not all tics are related to TS. There are many, many causes of secondary tics or tourettism. This article below is almost 10 years old now, but it does talk about many of the other conditions where tics present as a symptom. Because it's older, there are a number of newer causes that have been found that are not in this particular article.
This is just an example I'm giving and is not comprehensive...

http://www.scielo.br/pdf/rbp/v27n1/23707.pdf
Rev Bras Psiquiatr. 2005 Mar;27(1):11-7. Epub 2005 Apr 18.
Secondary tics and tourettism.
Mejia NI, Jankovic J.

One interesting model that you may be interested in considering your line of thought is Sydenham's Chorea. Strep Throat (GABHS) can also cause Rheumatic Fever if untreated and if the person is genetically predisposed. One neurologic sequelae of Rheumatic Fever (again, only in some people) can be a movement disorder called Sydenham's Chorea. Where PANDAS tics can occur immediately with the GABHS infection, strangely the Chorea doesn't usually begin for weeks or even months after the original infection.

Anyway, it's food for thought.
Much to say, but too little time.