iTunes doesn't sync all contacts

Hello everyone!

I have a small issue with syncing my contacts: The thing is, I would love to send someone a message through the new Message app for the mac. However, the number of that person was missing in the Message app. Well I was sure that the app takes the contacts from the address book and that's where I went to check - and indeed, that person is not in my address book. My address book says I have 208 numbers whereas my iPhone says I have 220. I found it strange because I sync my iPhone almost every day. However my iPhone reached its capacity limit today and I thought that might be causing some problems maybe? So I removed over 3000 photos and synced again - but nothing. Just won't sync those 12 missing contacts.

Can anyone help?

All help is appreciated 🙂

greets

PS: I have the iPhone 4, iOS 5.1