Clinical Characteristics

Clinical Characteristics

IQSEC2-related disorders are associated with intellectual disability, autism and seizures [epilepsy]. Not all people with a change in the IQSEC2 gene have all these features.

All males with an IQSEC2-related disorder will have intellectual disability, and some males will also have epilepsy [seizures] or epileptic encephalopathy [severe seizures occurring early in life, which may be difficult to treat].

Females who carry an IQSEC2 gene change can be very variably affected, even within the same family.

The following text summarises what is currently known about IQSEC2-related condition.


– Intellectual Disability

Males with IQSEC2-related disorder will have some degree of intellectual disability, ranging from mild to severe. Delays in language development are particularly common.

Females who carry an IQSEC2 gene change often have normal intelligence, however, some female carriers have mild learning or speech problems or borderline – mild intellectual disability. One female with an IQSEC2 gene change has been reported with moderate intellectual disability and seizures.

The severity can also vary between individuals with the same IQSEC2 gene change, even within the same family.


Behaviour/ Mental health

Autistic behaviours have been reported in some individuals with IQSEC2 gene changes, and some male individuals meet the diagnostic criteria for autism. Some male and female individuals with IQSEC2 gene changes have developed mental health conditions, including schizophrenia. Some males have distinctive repetitive movements of their hands (stereotypies).


– Seizures

Seizures have been reported in approximately 25% (1 in 4) of individuals with an IQSEC2-related disorder. These most commonly start in childhood or adolescence, and are often controlled by anti-seizure medication. Some patients have more severe seizure patterns starting in infancy.


– Physical features

Most individuals with an IQSEC2 gene change are healthy and look like unaffected members of their families. A strabismus (turn in the eye) has been reported in some people with the disorder. Some individuals have relatively slower growth of their heads resulting in smaller sized heads (postnatal microcephaly).

Most of these features are present from childhood. This is a genetic condition and is not related to environmental exposures or events during pregnancy or in early infant life.


Currently, there is no known cure for an IQSEC2-related disorder. However, early intervention and education programs can maximise learning and social development, and medications can help manage some symptoms.

Close monitoring by a paediatrician, comprehensive developmental assessment, hearing (audiometry) and eye tests (ophthalmology review) are recommended for children with IQSEC2-related disorder.

Any concerns about possible seizures or mental health conditions should be promptly discussed with your doctor so that these symptoms can be appropriately investigated and referral to a specialist (neurologist or psychiatrist) can be arranged.