Long-term follow-up of type 1 lissencephaly: survival is related to neuroimaging abnormalities

AIM To evaluate survival, clinical, and genetic characteristics of all patients with classic or type 1 lissencephaly born between 1972 and 1990 in the Netherlands, who at the time were enrolled in an observational study. METHOD We re-evaluated 24 patients (11 males, 13 females) for long-term follow-up and survival information. RESULTS Mean length of follow-up was 14 years (SD 9y 8mo). Eleven patients were alive at follow-up. All patients showed severe intellectual disability, intractable epilepsy, and complete dependency on care. Life expectancy was related to the severity of the lissencephaly on neuroimaging. Molecular analysis of the LIS1 gene was not possible at the time of the original study and was now requested by eight parents. This revealed a pathogenic nonsense mutation or deletion in seven patients. INTERPRETATION Our study provides information about the long-term course of lissencephaly and the relationship between lissencephaly severity and prognosis. It also shows that renewed attention to genetic counselling remains valued by families of patients with a severe congenital neurological disease.