If a mouse inherits a deletion in the shh enhancer, what effect would you expect to see?

You would expect to see abnormal limb development. 
A long-range shh enhancer regulates expression in the developing limb and fin is associated with preaxial polydactyly. Consequences of deletion and mutation of the limb enhancer in a mouse would be an abnormal development of the limb which is regulated by the Shh enhancer.

Abnormal limb development

From a high concentration to a low concentration.