Estimated occurrence1:100,000 live births.
Lissencephaly may have a genetic cause but may also occur due to toxins or virus infections in the uterus or the foetus, or due to insufficient blood supply to the foetus’ brain in early pregnancy. The genetic causes are often the result of a mutation on chromosome 7, 17 or the X-chromosome. There are more than 20 types of lissencephaly. It is not always possible to identify the causes.
The disease is characterised by large sections of the brain being smooth instead of convoluted. For the majority of those affected, this causes epilepsy and motor and cognitive impairment of varying levels of severity. Cerebral palsy and muscle weakness are also common. A distinctive appearance sometimes occurs, as do malformations of hands, fingers and toes.
Agyria, lissencaphaly type 1, classic lissencephaly (LIS 1).
Oral motor development is delayed. Difficulties with eating and swallowing are common, as are respiratory problems. The majority of those affected have speech and language development impairments. Biting habits/grinding teeth in the daytime often occur, as well as reduced saliva control/drooling. Many have dry mouth due to medication. There is an increased risk of dental trauma through epileptic seizures and balance problems, among other things.
Advice on follow-up and treatment
- Early contact with dental services for intensified prophylactic care and oral hygiene information is essential.
- Training in oral motor skills and extra stimulation in cases of eating disorders, speech difficulties and impaired saliva control may be necessary.
- Speech, language and communication training is often warranted.