Iranian Journal of Child Neurology

Abstract

Objective

Angelman Syndrome (AS) is a genetically determined syndrome that has a unique behavioral phenotype. This syndrome is described as jerky ataxia and an unusual happy facial expression with pathological laughter. Severe mental retardation is a unique feature of the syndrome, together with microbrachycephaly and abnormal electroencephalographic findings with or without clinical seizures. The patients cannot speak or at most, they have a vocabulary consisting only of a few words. The genetic abnormality of AS has been located on chromosome 15q11-q13. Patients with AS mostly have deletions on the maternally derived allele (75-80%) while some of them show paternal  uniparental disomy (~2%) or a rare imprinting mutation developmental disorder caused by deletion of the maternally-inherited chromosome 15q11-13. A 2.5-year-old girl is presented. Clinical suspicion of AS was raised at the age of 27 months when she presented with mental retardation and epilepsy, absence of speech, inability to gait and paroxysmal episodes of laughter. Moreover, she had facial dysmorphic features such as microbrachycephaly,  mid-facial hypoplasia, macrostomia and a prominent mandible. Chromosomal analysis revealed 46 xx with the deletion of 15q chromosome (15q11q13-snrpn/ic) Our patient met the classical phenotype and genotype of AS.