You really can't say if it's a genetic or social cause.

Asthma is a complex disease with genetic and environmental causes.

Most of the cases are sporadic (no known genetic cause).

Within this area, the search for a genetic cause of the disease has continued.

In about 30% of the cases, a genetic cause can be identified.

This can help determine whether a disease or a certain trait has a genetic cause.

Last week, researchers in London reported that the disease might also have a genetic cause.

The genetic cause of this disorder was described in 2007.

So researchers are doing studies to look for a genetic cause.

Both factors have made it hard for researchers to find a genetic cause.