The hypodermis is the innermost and thickest layer of the skin. It invaginates into the dermis and is attached to the latter, immediately above it, by collagen and elastin fibres. It is essentially composed of a type of cells specialised in accumulating and storing fats, known as adipocytes.
Fatal familial insomnia Fatal familial insomnia (FFI) is a very rare, autosomal dominant inherited, disease of the brain. It is caused by a mutation in a protein called prion protein (PrP): asparagine-178 is replaced by aspartic acid.
Insomnia (in-SOM-ne-ah) is a common sleep disorder. People who have insomnia have trouble falling asleep, staying asleep, or both. As a result, they may get too little sleep or have poor-quality sleep. They may not feel refreshed when they wake up.