Mouse models of Wolf-Hirschhorn syndrome.

Subtelomeric deletion syndromes represent a significant cause of mental retardation and craniofacial disease. However, for most of these syndromes the pathogenic genes have yet to be identified. Currently there is every indication that identification of these genes will be a slow process if we continue to rely strictly upon clinical data. An alternative approach is the use of mouse models to complement the patient studies. Wolf-Hirschhorn syndrome (WHS), caused by deletions in 4p16.3, is the first recognized subtelomeric deletion syndrome. As with other syndromes of this class, WHS has not yet been subjected to an intensive, systematic analysis using mouse models. Nonetheless, a significant number of targeted mutations have been introduced into mouse genomic region, 5B1, which is orthologous to 4p16.3. Included among these mutations are a series of deletions approximating the deletions in some patients. The mouse lines carrying these deletions display a remarkable concordance of phenotypes with the human patient's characteristics, strongly indicating that the mouse models can be used to phenocopy WHS. In this review, we will catalog the currently existing targeted mutations in mice in the regions orthologous to the WHS critical regions. For each mutation we will discuss the resulting phenotype and its potential relevance to the pathogenesis of the syndrome. Further, we will describe how the phenotypes of some of the mutations suggest new directions for the clinical studies. Finally we will outline approaches for the efficient creation of new mouse models of WHS going forward.