Figure 2.

Types of genetic variants that contribute to epilepsy and potential targets for therapeutic strategies depending on the effect of the pathogenic variant. (A) Different pathogenic variants can cause epilepsy, including (i) sequence variants, (ii) expansion repeat variants, (iii) copy-number variants, and (iv) epigenetic variation, such as altered DNA methylation. Note that copy-number variants can also include gene or intra-gene level changes. Also, different types of variants can also act together, for instance, a repeat expansion may cause increased hypermethylation of a gene promoter leading to its inactivation. (B) The effect a variant has on downstream pathways can lead to either a loss or gain of function and therapeutic strategies can target the affected protein as well as substrates or downstream products in the pathway depending on the effect of the variant.