I'm not aware of any organisation/team called MOSAICS. It may be a local thing?
Of course, paed could mean they are referring to the geneticist to investigate the possibility of a "mosaic" condition. You can wiki it, but basically it's if there is a mutation in the very early days of baby's development - say they are just a clump of 4 cells and one cell goes a bit wrong. That cell will go on to make up specific tissue in the body, so the child may seem to be partially affected by a condition, or have it more mildly than usual.