<unk>  is a genetic condition caused by a deletion of genetic material within one of the two copies of chromosome 18. The deletion involves the<unk>  section of<unk>  and typically extends to the tip of the long arm of chromosome 18.
Distal 18q-
Dup15q
Xq28
Ring chromosome 18
Ring chromosome 15
714-X
Ring chromosome 22
18p-