Hand flapping and crossing eyes

Hi,

I have a 2.4 year old son.  He has been flapping his hands when he is excited since he was about 20 months of age.  He flaps from elbow to hand, or from the wrist to fingers.   Recently he has begun crossing his left eye in while flapping (we see it every few days or so).  I've seen the eye cross in without the flapping, but it usually happens simultaneously.

He is normally developing in all areas.  He's very verbal and uses pronouns correctly, and speaks in 6- 10 word sentences.  He does echo phrases or sentences we say sometimes, but mostly he initiates and engages in regular conversation.  Isn't echoing normal in a two year old?  His voice tone is normal.  He's also very social, and frequently calls out to other kids to show them something.  For instance, this morning in the sandbox he shouted, "Hey Boy, come look at this.".   He likes to talk to people, and he often begins conversations by saying, "Remember the......" even when the person he is talking to won't remember it since they weren't there.  I just assumed he'd been overgeneralzing the use of the expression "Remember the", but maybe that's not normal????

He started crawling at 11 months and walking at 13 months.  He's very agile and energetic and doesn't appear clumsy, although he is very cautious about jumping down from things on his own.  He also has great fine motor control- he  started drawing pea pod people last week. :)

He was diagnosed with mild galactosemia as a newborn, but has not been on a restrictive diet of any kind.  Although his enzyme level for processing galactose is low, his body functions well.  We are going to see the metabolic geneticist again this week to have his levels rechecked, and to make sure it is not causing the stereotypical behaviors.  

We are also seeing an ophthalmologist in early July, and a naturopath specializing in neuropathy next week. He clearly isn't autistic, but why the stereotypical behavior? I'm worried.  

Does anybody have any other suggestions for us?  Prior to having children I worked in sp. ed. so I'm very aware of the power of early intervention, but since he's not showing any delays, I'm not sure where to turn.  

Thanks in advance.

[Chetters]

Wanted to update this post.  Jack was just diagnosed with Stereotypic Movement Disorder.  He is not on the spectrum and has no delays, he just exhibits the stereoypic movements.  It's pretty rare, but we were told some grow out of it, and those that don't learn to control/hide it.  It feels good to have answers.