Sleep Disorders, Epilepsy Improve in Adolescents and Adults With Angelman Syndrome, Study Shows

Sleep disturbances and epilepsy, which affect about 80 percent of pediatric Angelman syndrome patients, improve over the years, new Italian study shows.

The study, “Epilepsy and sleep disorders improve in adolescents and adults with Angelman syndrome: A multicenter study on 46 patients,” appeared in the journal Epilepsy & Behavior.

The research team was led by Chiara Sueri, MD, and Edoardo Ferlazzo, MD, PhD, from the Regional Epilepsy Center, “Bianchi-Melacrino-Morelli” Hospital, in Reggio Calabria, Italy. Ferlazzo also is affiliated with the Department of Medical and Surgical Sciences, “Magna Græcia” University of Catanzaro, in Italy.

Sleep disorders and epilepsy are among frequent disturbances in AS, which exhibits clinical variability associated with the specific deficiency in the maternal copy of the ubiquitin protein ligase E3A (UBE3A) gene.

Epilepsy occurs in more than 80 percent of AS patients and starts in infancy or early childhood, with seizures of varied types. Sleep disturbances are observed in up to 80 percent of AS patients, consisting of disrupted sleep-wake cycle, multiple nocturnal awakenings, diminished need for sleep, and difficulties in falling asleep.

Abnormalities in electroencephalography (EEG) (electrical activity in the brain, essential for neuronal communication) are observed consistently in the first two years of life, but may not correlate with epileptic seizures in AS patients.

Extensive characterization of clinical manifestations in AS is available only from pediatric patients. In contrast, conflicting data from older subjects is derived from questionnaires completed by family members, phone interviews with caregivers, or small retrospective studies focused on specific genetic features or institutionalized patients.

So, the authors of this study aimed to evaluate the long-term outcome of epilepsy, sleep disorders, and EEG in a large group of adolescent and adult AS subjects, in order to provide better management of these age groups.

The study enrolled 46 patients with genetically confirmed AS, aged 14-45 years, who were being followed in three tertiary epilepsy centers (24 patients) or attending the meetings of the Italian Organization for AS (OrSA) (22 patients).

The scientists retrieved retrospective clinical and EEG results from hospital archives or family documents. All patients underwent an index evaluation (IE) at the last visit at tertiary centers or single attendance at an OrSA meeting. At IE, the researchers interviewed caregivers about patients’ medical history. Caregivers also filled out questionnaires on sleep disorders and daily-living skills. Patients underwent general and neurologic evaluation.

The authors observed that 91.3 percent of patients exhibited seizures during childhood. However, all subjects showed improvements over the years. Importantly, 64 percent of epileptic patients became seizure-free at a median age of 10 years, and four remained seizure-free even after withdrawal of anti-epileptic drugs. The data also showed that seizure frequency was not influenced by specific AS genetic subtype.

Conversely, 84.8 percent of patients showed sleep disorders during childhood, which improved in 69 percent over the years, matching results of earlier studies.

At IE, daily-living skills corresponded to a mental age of 1.6 years or lower in 63 percent of patients. EEG showed typical AS patterns in 76.1 percent, independent from presence and evolution of epilepsy. Furthermore, EEGs recorded from 10 patients were stable, comparing infancy/childhood and adolescence/adulthood.

Overall, the results show a favorable outcome in regards to the evolution of sleep disruptions and epilepsy in AS patients. However, “improvement of epilepsy or sleep disorders should not disregard the clinical suspicion of AS in adolescent or adult patients with suggestive features,” the authors wrote.

Furthermore, the data also show that “drug withdrawal might be considered in the management of epilepsy” in these patients.