Hi Tracy, we have a 15month old daughter Megan who was diagnosed with OMA at 6 months. She sat at 8 months and walked at 17 months.
I think when you look on this web site it can be very frightening as a lot of the children on here have other problems as well as OMA. I think the fact that your son sat up and crawled so early is a very good sign that he wont have any problems reaching the "normal" milestones.

Megan is a little unbalanced when she walks and falls a little bit more often, but other than that she is getting on very well. She says some words such as Mum, dad, Nan and so on, but maybe a little behind verbally.

It can be very worrying at times because of the unknown, but it sounds to me like your son is like Megan and through only having the OMA, may experience slight delays with some things but get there in the end.

If you would like to talk more, then feel welcome to e mail me
Mandy (UK)