Developmental and epileptic encephalopathies (DEEs) are an early-onset form of epilepsy that result in aggressive and recurring seizures, possibly leading to severe cognitive and developmental impairment. While most genetic variants that cause DEE reside in the coding regions of genes, splice site variants can also be pathogenic. Splice site variants are changes in the DNA close to, or on, the exon-intron boundary, which can cause aberrant splicing, resulting in exon exclusion or intron inclusion within spliced RNA, generating a protein that is non-functional, partially functional, or aberrantly expressed. If aberrant splicing occurs, it could have pathogenic consequences, but predicting which variants near splice sites will have an effect on splicing is difficult. This raises the need to investigate splice-site variants. My work is concentrated on potential splice site variants in three genes associated with DEE: SYNGAP1, SCN1B, and WWOX. SCN1B codes for voltage-gated channels within the brain, SYNGAP1 is associated with postsynaptic signaling, and WWOX acts as a tumor suppressor and is vital in brain development. DEE genes are primarily expressed in the brain, a tissue that is unavailable from most patients, making splicing studies in these genes difficult. I was able to successfully amplify targeted regions of SCN1B, SYNGAP1, and WWOX in RNA isolated from blood and fibroblast, demonstrating the efficacy of using these more easily accessible tissues in my studies. The lab has now collected fibroblast samples from DEE patients with potential splice site variants in WWOX and SCN1B. I will use RNA extracted from these fibroblasts to confirm whether the splice site variants in WWOX and SCN1B cause aberrant splicing, and what the specific consequences of this aberrant splicing is on the protein-coding sequence of these genes. In the future, we also plan on collecting fibroblasts samples with variants from SYNGAP1 as well.