Thanks to Lacey, I now know that I was wrong about the types of Down syndrome. I've corrected the posts below. All Down syndrome is Trisomy 21. The 3 types are Nondisjunction, Translocation and Mosaicism. I have a call into the doctor's office to find out what type Lillie has (again). Apparently the nurse I spoke to before doesn't have a clue what she's talking about!!
Update: I looked at the report when we were at Dr. C's last week. It doesn't say which type, but it says that all cells have the extra 21st chromosome, which rules out Mosaicism, and it doesn't say that the 21st chromosome is linked to another chromosome, which rules out Translocation. So Lillie has Nondisjuction Trisomy 21...the most common form of Down syndrome. Now we finally know!