Children and adults with a STAG1-related condition can show many of the following features, but each person is unique:
• Development and learning
o Delayed sitting, standing, and walking
o Learning difficulties ranging from mild to severe
o Speech delay; some children speak in short phrases or sentences, others use very few words and may rely on other ways to communicate
• Behaviour
o Features of autism spectrum disorder (e.g. differences in social interaction, restricted interests, repetitive behaviours)
o Attention problems, hyperactivity, anxiety, or challenging behaviour in some individuals
• Neurology
o Low muscle tone (hypotonia) in infancy or, less often, increased tone or spasticity
o Seizures in a proportion of individuals, which may start in childhood
• Physical features
o Subtle facial features, such as a relatively large mouth, deep-set or widely spaced eyes, and other small differences in facial shape
o Differences in head (slightly small or large head in some)
• Other possible features
o Heart defects present from birth
o Hearing loss or ear anomalies (e.g. small or differently shaped ears)
o Vision problems, including short- or long-sightedness, squint, or small eyes
o Spine or bone changes (e.g. scoliosis, vertebral anomalies, joint contractures, or clubfoot)
o Undescended testes in boys
Not all features are present in every individual. Some children are only mildly affected, while others have more complex medical and developmental needs.
STAG1