SNP Shot: Genomic Insights

SYNGAP1-related intellectual disability is a brain-based condition leading to intellectual disability, ranging from moderate to severe, that becomes noticeable in early childhood. The initial signs usually involve delays in speech and movement milestones, like sitting, standing, and walking. Hypotonia, or weak muscle tone, is common and further hinders motor skill development. Some individuals may experience developmental regression, losing previously learned abilities. Additional characteristics often include epilepsy (recurring seizures), hyperactivity, and autism spectrum disorder, a condition affecting communication and social skills. Epilepsy is very common in those with SYNGAP1-related intellectual disability, and approximately half also have autism spectrum disorder.

Inheritance:

SYNGAP1-related intellectual disability is an autosomal dominant disorder. This means that having just one altered copy of the SYNGAP1 gene in each cell is enough to cause the condition. Nearly all cases arise from spontaneous new mutations in the gene, occurring in individuals with no family history of the disorder. Although rare, there has been at least one documented instance of an affected individual inheriting the mutation from a parent who also had the condition.