Angelman syndrome presenting with a rare seizure type in a patient with 15q11.2 deletion: a case report

Angelman syndrome, a neurodevelopmental genetic disorder associated with abnormalities in chromosome15q11-q13, is inherited from the mother. Epilepsy is seen in 85 % of children with Angelman syndrome within the first 3 years of life and is often severe and difficult to control.

We report a case of a baby boy who presented at 13 months of age with a history of acute gastroenteritis and marked gross motor and speech developmental delay. He was found to have a microdeletion of the chromosome 15q11.2 region confirming the diagnosis of Angelman syndrome. He was the first child born to healthy, unrelated Sinhalese parents. The child had generalized extensor spasms involving both upper limbs and the head beginning at the age of 9 months, and he developed flexor and extensor spasms at the age of 13 months. His facial appearance was characteristic of Angelman syndrome. His electroencephalographic pattern did not correspond to any other of the patterns previously described in patients with Angelman syndrome. He had extensor and flexor spasms, which are rarely described in patients with Angelman syndrome. These symptoms responded to a combination of valproic acid and clonazepam.

Angelman syndrome due to a microdeletion of the chromosome 15q11.2 region is often not diagnosed in infancy. Extensor and flexor spasms are not typically described seizure types in Angelman syndrome, and our patient’s seizures responded well to a combination of valproic acid and clonazepam. Clinicians should suspect other possible seizure types in patients with Angelman syndrome and should treat the patient appropriately.