SNP Shot: Genomic Insights

Angelman syndrome is a genetic condition impacting mainly the nervous system. Key features involve developmental delays, intellectual disability, significant speech difficulties, and problems with coordination and balance, known as ataxia. Epilepsy (recurrent seizures) and microcephaly (small head size) are also frequently observed in affected children. The developmental delays are typically noticeable between 6 and 12 months of age, with other typical signs emerging in early childhood.

Children with Angelman syndrome often exhibit a cheerful and easily excited disposition, characterized by frequent smiles, laughter, and repetitive hand movements. Hyperactivity and a reduced attention span are common traits. Many affected children experience sleep disturbances and require less sleep than their peers.

As individuals with Angelman syndrome age, their excitability often decreases, and sleep patterns tend to improve. However, intellectual disability, severe speech impairment, and seizures persist throughout their lives. Adults may develop characteristic "coarse" facial features. Additional common traits include unusually light skin and hair, and scoliosis (an abnormal curvature of the spine). The life expectancy for individuals with Angelman syndrome is generally considered to be near normal.

Inheritance:

The majority of Angelman syndrome cases are not inherited. This is especially true when the cause is a deletion on the maternal chromosome 15 or paternal uniparental disomy. These genetic alterations arise spontaneously during the development of eggs or sperm, or in the early stages of embryonic development. In these situations, there is usually no family history of the disorder. In rare instances, a genetic alteration leading to Angelman syndrome can be passed down through families. For example, a mutation in the UBE3A gene, or in the regulatory DNA region that activates the gene, can be inherited.