Background:

The spectrum of lissencephaly (LIS) corresponds to a group of serious brain malformations in the cortex caused by a failure in neuronal migration. The spectrum includes agyria, pachygyria and subcortical band heterotopia (SBH). It has generally been divided into two categories: classic lissencephaly or type I, and cobblestone lissencephaly or type II.

Objective:

The objective of the study was to describe clinical, neuroimaging, and neurophysiological features of pediatric patients with lissencephaly (LIS) type I.

Methods:

Retrospective study of children with the diagnosis of LIS, who were admitted to the National Institute of Pediatrics in Mexico City from January 2009 to December 2019.

Results:

We included a total of 22 patients, 15 (68%) were male. Age at diagnosis: 4 (18%) children under 1 month due to ventricular dilation on ultrasound and epileptic spasms; 13 (59%) children of 1 month-1 year due to microcephaly, drug-resistant epilepsy, and neurodevelopmental delay; 5 (22%) children over 1 year. Regarding etiology: 6 cases were due to cytomegalovirus, 1 to Zika, and 1 to microdeletion diagnosed as Miller-Dieker syndrome. All (100%) had neurodevelopmental delay, 19 (86%) intellectual disability. Epilepsy was found in 19 (86%), of these 6 had epileptic spasms, 7 had West syndrome, and 5 evolved to Lennox-Gastaut. Drug-resistant epilepsy was present in 17 (77%) patients. Regarding comorbidities: 15 (68%) had gastroesophageal reflux disease and 14 (63%) had recurrent pneumonia. Regarding neuroimaging findings, paquigiria was present in 9 (41%) children. Two children died, they had diffuse agyria.

Conclusions:

LIS type I includes pathologies with a poor prognosis, manifested predominantly in the 1st year of life. All patients have delayed psychomotor development, refractory epilepsy and were associated with different comorbidities. Genetic and neuroimaging studies are important to make an accurate diagnosis, predict evolution, offer genetic counseling, and palliative treatment.

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