Last Wednesday we took Emma to see her neurologist. We gave him the MRI CD and the printed reports with the findings from Dr. Nelson (the neuroradiologist at Children's Hospital of Los Angeles).
Dr. Imbus had never heard of rhombencephalosynapsis, which isn't surprising given its rarity. He had to look it up in his big pediatric neurology book, and even that only had 2 sentences on it! But he looked at the images, and said that he saw the same things described by Dr. Nelson. When I asked him why no one had ever spotted this problem before, Dr. Imbus just smiled and said, "Because Emma's MR images were never read by Nelson before." Then he explained that Dr. Nelson is one of the best neuroradiologists in the world (possibly THE best in the world).
So...the bottom line is that Emma definitely does have rhombencephalosynapsis. I asked Dr. Imbus if this explains Emma's tone issues and he said yes, absolutely, because people with damage to the cerebellum are generally "floppy", as he put it.
He asked if there were any articles in the literature about TAR Syndrome and cerebellar anomalies. I couldn't remember any, but sure enough, when I got home and Googled "TAR Syndrome cerebellum" I did find some. So it's possible that this cerebellar malformation is just another TAR Syndrome thing. I'm planning to write an email to Dr. Judith Hall (the doctor who coined the name "Thrombocytopenia Absent Radii Syndrome") to ask her what she knows about brain anomalies and TAR Syndrome.