Lack of skin in a certain area of the body --- hypo[what]?
First, this is not an area where I have any education or experience. However, out of curiosity I consulted google and found two genetic castle diseases that should be relevant to your question:


Epitheliogenesis imperfecta (vetbook.org)
Ectodermal dysplasia


Both diseases are very serious, and Epitheliogenesis imperfecta is fatal (due to infections). 

I chose not to include any pictures of the diseases in this answer since they often look quite horrible, and some people might find them unsettling. If you click the links there are pictures of the conditions though.

A "similar" condition in humans might be  Epidermolysis bullosa, which is caused by decreased anchoring between dermis and epidermis, which cause a very fragile skin:


  Epidermolysis bullosa (EB) is a group of mainly inherited connective tissue diseases that cause blisters in the skin and mucosal membranes, with an incidence of 20 per million newborns in the United States.[1] It is a result of a defect in anchoring between the epidermis and dermis, resulting in friction and skin fragility. Its severity ranges from mild to lethal.  


(Wikipedia)