Editorial comments follow each reference in italics .
It is important to note that the medical and scientific understanding of these disorders is changing rapidly. For this reason, you may read statements in one paper that are directly contradicted by another paper. Beyond this, it is possible that current understanding may change, with the result that statements in the most recent papers may be altered in the future. The comments in italics below each article are the opinion of the author and do not necessarily reflect the policy or position of the National Insititutes of Health, The Pallister-Hall family support group or any other organization to which the editor is affiliated. If you have suggestions about additions or changes to this list, please contact Leslie Biesecker .