Phenotypic traits and family history in patients with 22q11.2 deletion syndrome and generalized epilepsy: A multicenter case-control study.

Objective: This study was undertaken to characterize the clinical and genetic features of patients with 22q11.2 deletion syndrome (22q11.2DS) and generalized epilepsy compared with 22q11.2DS individuals without epilepsy.

Methods: This multicenter case-control study included 28 patients with 22q11.2DS-related generalized epilepsy and compared their data with 56 age-matched 22q11.2DS controls without epilepsy. Clinical and electroencephalographic features, neuropsychiatric and systemic comorbidities, family history of epilepsy, and genetic findings were collected.

Results: Generalized tonic-clonic seizures and myoclonic seizures were the most common electroclinical presentations, with a broader range of seizure type combinations also documented. Most patients achieved seizure remission with antiseizure medications, with only 4% exhibiting drug resistance. A higher prevalence of family history of epilepsy was observed among patients with 22q11.2DS-related generalized epilepsy compared to nonepilepsy controls, even when limiting the analysis to patients with known de novo deletions. No differences in deletion size or location were observed between the groups. Multivariable logistic regression analysis identified family history of epilepsy, intellectual disability, and lack of skeletal abnormalities as independent factors associated with generalized epilepsy, whereas a history of psychosis was significant only in univariable analysis.

Significance: This study provides a detailed characterization of generalized epilepsy in individuals with 22q11.2DS and highlights specific associated comorbidities. The higher prevalence of family history of epilepsy among cases suggests that genetic factors beyond the 22q11.2 deletion influence the development of the epilepsy phenotype, providing new insights into the genetic underpinnings of phenotypic variability in this syndrome.