A deletion is nothing more than the loss of a fragment of a chromosome. Microdeletion (otherwise known as microdeletion 2q33.1 syndrome) involves a specific number of genes, which in turn leads to defects and health problems. Research shows that haploinsufficiency of the STAB2 gene (a gene involved in brain and craniofacial development) is responsible for the development of this syndrome. Another gene called PGAP1 (involved in facial formation) has also received particular attention. It is the PGAP1 mutation that is present in the 2q33.1 syndrome. Research shows that the 2q33.1 microdeletion syndrome can be inherited or reappear.