Having a sudden problem in that not all my contacts are syncing

Never had a problem before but now some of my contacts (on my MacBook) no longer sync to my iPhone 3.

Always the same ones. Nothing to do with groups as I don't have any.

Have synced with the replace contacts on the iPhone with those on the MB but all still do not sync neither does syncing with the contacts option unticked which deleted all contacts on the iPhone but when resyncing with contacts synced the same ones were still missing on the iPhone.

Any ideas much appreciated

Should add that I am syncing via USB as no iCloud etc.