Benign rolandic epilepsy (BRE) and the centrotemporal spikes that identify it on an EEG are more common in siblings and other close relatives of children with this syndrome than in the general population. This suggests that a genetic tendency probably is involved in producing this form of epilepsy.

The likelihood that a person who inherits this tendency will actually develop the disease most likely depends on several factors, including the person's age. The likelihood is very low at birth, becomes almost certain between ages 4 and 16, and almost disappears after age 40. Scientists call this kind of pattern "age-dependent penetrance."

It wasn't possible to find definite evidence of a particular gene until the early 1990s, however, when a new gene-hunting technique called linkage studies began to be used. This technique traces patterns of heredity in large families at high risk for a particular disease. The scientists look for the location of a disease-causing gene mutation by identifying traits that are inherited along with it.

Linkage studies performed in families that include many people with BRE suggest that band 14 of the long arm of chromosome 15 (written by scientists as 15q14) is the most likely location for the gene responsible for some cases—but not all—of this syndrome. The band 15q14 appears to be involved in regulating the excitability of neurons (nerve cells) in the brain, so it may contribute to seizure susceptibility. Researchers have not discovered exactly how the gene produces BRE.