Autistic features in Angelman Syndrome: A Longitudinal Analysis of the Autism Diagnostic Observation Scale

Angelman syndrome (AS) is a rare neurogenetic disorder characterized by, severe developmental delays, little to no speech development, seizures, gross and fine motor deficits, stereotypical behavior, and anxiety. There are four genetic subtypes of AS: deletion, UBE3A mutation, Paternal Uniparental Disomy (UPD), and Imprinting Defect (ID). Former research showed that there is a high comorbidity between AS and autism spectrum disorder (ASD). However, little is known about how autism symptoms develop over time in AS. This study aimed to investigate how the severity of autism symptoms develop over time for the total group of AS children, per genetic subtype, and per gender. The sample consists of 41 children with AS who were tested two to four times at the center of expertise in Rotterdam. The ages ranged between 2.7 and 18.6 years, and the average time between the first and last test date was 4.2 years. The severity of autism symptoms was measured with the Autism Diagnostic Observation...Show moreAngelman syndrome (AS) is a rare neurogenetic disorder characterized by, severe developmental delays, little to no speech development, seizures, gross and fine motor deficits, stereotypical behavior, and anxiety. There are four genetic subtypes of AS: deletion, UBE3A mutation, Paternal Uniparental Disomy (UPD), and Imprinting Defect (ID). Former research showed that there is a high comorbidity between AS and autism spectrum disorder (ASD). However, little is known about how autism symptoms develop over time in AS. This study aimed to investigate how the severity of autism symptoms develop over time for the total group of AS children, per genetic subtype, and per gender. The sample consists of 41 children with AS who were tested two to four times at the center of expertise in Rotterdam. The ages ranged between 2.7 and 18.6 years, and the average time between the first and last test date was 4.2 years. The severity of autism symptoms was measured with the Autism Diagnostic Observation Scale (ADOS). The course of autism symptoms over time was analyzed with a linear mixed effects model in R. Results indicated that the severity of symptoms does not change over time (p = .220). In addition, it was found that children with a deletion presented with more autism symptoms on baseline compared to the other genetic subtypes (for all comparisons the p-value was < .001). Longitudinally, we found that children with a deletion develop differently from children with UPD regarding the severity of autism symptoms (p = .012). Children with a deletion stay stable in the severity of autism symptoms over time whereas children with UPD decrease in the severity of autism symptoms. For gender, we found that boys present with more autism symptoms at baseline than girls (p = .046). Longitudinally, no differences were found in how boys and girls develop regarding the severity of autism symptoms (p = .356). This study was the very first to investigate how autism symptoms per genetic subtype and per gender develop over time in children with AS. The results will help to inform the clinicians and caregivers about the prognosis of autism symptoms in Angelman Syndrome.Show less

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Autistic features in Angelman Syndrome: A Longitudinal Analysis of the Autism Diagnostic Observation Scale