ZSWIM6

Clinical Characteristics

The main clinical features of ZSWIM6-related intellectual disability are:

  • Intellectual disability: To date, all individuals with ZSWIM6-related disorder have some degree of intellectual disability, typically in the severe range. All individuals have required special schooling and support to live independently as adults.
  • Speech: All affected individuals had delays in their speech and language development. Some individuals are able to communicate using resources such as picture exchange communication systems.
  • Behaviour: Some but not all individuals with ZSWIM6-related intellectual disability have been described as being on the autistic spectrum. This seems to be because they may have repetitive (repeated) movements, are very active and have limited play skills; however, most are described as being socially aware and responsive, and show strong attachment and affection to their families.
  • Movement and muscles: All individuals have been described as being ‘floppy’ babies (low muscle tone) and are slower to achieve their early motor milestones, such as learning to roll, sit and walk. Many individuals when they are up and walking can be unsteady on their feet (‘ataxic’). Some may need a wheelchair to help with mobility in later life. Some individuals have a progressive spasticity (increased muscle tone) and/or neuropathy (nerve condition).
    Unusual movements of the body have been described including a hand tremor, difficulty coordinating hand and tongue movements and leg stiffness. These differences are not present in all individuals. 
  • Seizures: Some individuals have seizures that have been well controlled with medication.
  • Gastrointestinal: People with ZSWIM6-related intellectual disability may have difficulties gaining weight as infants and ongoing difficulties with feeding and eating. Gastroesophageal reflux (acid reflux) and constipation are common but respond to treatments.
  • Facial features: Some individuals have been described as having a slightly longer face with a more prominent chin, downturned corners of the mouth and a tendency to hold the mouth open. Generally individuals do not significantly differ in appearance from other (unaffected) members of their family.

We are not aware of a particularly increased chance of other medical conditions.