Evaluation of epilepsy in 8p-related disorders

8p-related disorders are genetic conditions associated with chromosomal rearrangements on the short arm of chromosome 8. This study aimed to characterize the epilepsy phenotype in patients with 8p-related disorders seen at Children's Hospital Colorado (CHCO) and/or recorded in the Project 8p Foundation Natural History Study. Key objectives included determining epilepsy prevalence, typical age of seizure onset, efficacy of treatment, and EEG features. A retrospective chart review was conducted for patients seen in the CHCO Neurogenetics Multidisciplinary Clinic and Project 8p Database. Clinical data including demographics, genotype, epilepsy history, and EEG findings were collected. The cohort included 162 unique patients with 8p-related disorders (42 at CHCO, 120 from the Project 8p Natural History Study). Overall, 32 % of patients (53/162) had experienced at least one lifetime seizure: 37 % (30/81) of those with Invdupdel(8p), 35 % (16/46) with 8p deletions, and 15 % (4/26) with 8p duplications. Average age of seizure onset was 3.4 years, with a range from neonatal onset to 16.9 years of age. Among CHCO patients with epilepsy (14/42, 33 %), only one had intractable epilepsy, while 9 became seizure-free, including 5 off medications. EEG abnormalities were present in 18/42, 43 % of the CHCO patients. This study provides the first detailed analysis of epilepsy in a large cohort of patients with 8p-related disorders. While epilepsy is relatively common, it is typically well controlled. Genotype-specific patterns emerged, with Invdupdel(8p) associated with the highest epilepsy prevalence and 8p duplication with the lowest. Further research in larger cohorts is warranted to validate these findings.