Your sleeping habits affect gene expression in hundreds of ways that aren't yet well-understood, but sleeping too little sure seems bad.
So researchers at the University of Surrey analysed the blood of 26 people after they had had plenty of sleep, up to 10 hours each night for a week, and compared the results with samples after a week of fewer than six hours a night.
More than 700 genes were altered by the shift. Each contains the instructions for building a protein, so those that became more active produced more proteins - changing the chemistry of the body. ...
... the key findings were the effects on inflammation and the immune system as it was possible to see a link between those effects and health problems such as diabetes.
Inflammation alone is has all sorts of negative health effects.
Key takeaway: give sleep as much priority as exercise and eating right.