Families

STAG1-related condition is a rare genetic condition that affects brain development and can also involve other parts of the body.

People with a change (variant) in the STAG1gene often have:
•    Delay in reaching developmental milestones
•    Learning difficulties or intellectual disability
•    Delay in speech and language
•    Behavioural differences, which may include autism spectrum features
•    Certain facial features that may be shared between affected individuals

Some people also have seizures (epilepsy) or problems with vision, hearing, the heart, or joints. Not every person has all of these features, and the severity can vary widely, even within the same family.

STAG1-related disorder is usually caused by a new (de novo) genetic change that is not present in either parent. In some families, it can be passed on from an affected parent to their child in an autosomal dominant way. This means that a person with a STAG1variant has a 50% (1 in 2) chance of passing it on in each pregnancy.

Because the condition has only been recognised in recent years and only a small number of individuals have been reported worldwide so far, we are still learning about its full range of features and long-term outlook.