Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!

Malformation of the cerebral cortex with abnormal facies. Classic lissencephaly, also known as lissencephaly type I, is a brain malformation that may occur as an isolated abnormality (isolated lissencephaly sequence) or in association with certain underlying syndromes (e.g., Miller-Dieker syndrome, Norman-Roberts syndrome). The condition is characterized by agyria or pachygyria of the gyri of the cerebral cortex, causing the brain's surface to appear unusually smooth. In infants with classic lissencephaly, microcephaly is usually present. Other clinical features include seizures, severe or profound mental retardation, feeding difficulties, growth retardation, and impaired motor functions.

Lissencephaly Syndrome, Type I; MDLS.

It is undoubtedly a rare condition. In 1991, it was reported in the only published epidemiological study performed in the Dutch population that the prevalence was 11.7 per million live births. Since then, the larger use of MRI diagnosis has most certainly contributed to make the incidence and prevalence higher. It is suggested that 25-30% of patients with classical lissencephaly have Miller-Dieker syndrome.

Usually sporadic cases with no familial inheritance; in most cases, changes (mutations) of at least two different genes have been implicated in isolated lissencephaly: a gene located on chromosome 17 (known as LIS1) and a gene located on the X-chromosome (deletions or mutations of gene LIS1 on chromosome 17 p13.3).

Various possible causes of isolated lissencephaly include viral infections, insufficient blood flow to the brain during fetal development, and certain genetic factors.

Clinical picture and central nervous system imaging: smooth brain surface (with or without pachygyria), thickened cortex, absent or hypoplastic corpus callosum, small brainstem.

Postnatal failure to thrive with death before age 2 years. Microcephaly with bitemporal narrowing, vertical ridging, and furrowing of the skin on the forehead; up-slanted palpebral fissures; small nose with anteverted nostrils; protuberant upper lip and micrognathia. May have cardiac defect (atrial septal defect, ventricular septal defect, tetralogy of Fallot). Severe mental deficiency with hypotonia progressing to spasticity and seizures. Dysphagia and gastroesophageal reflux are common.

Check for chronic aspiration pneumonia (radiography), presence of a cardiac defect and possible undernutrition; antiepileptic and antireflux treatment should be continued until the morning of anesthesia.

Classic considerations for infants at risk for difficult intubation and gastroesophageal reflux; adapt choice of drugs and technique to the cardiac defect.

Antiepileptic treatment is usually complex: possible induction of cytochrome P-450 enzymes. In presence of cardiac anomalies, antibiotherapy must be considered.

Hard Syndrome: Characterized by type II lissencephaly in association with retinal dysplasia, obstructive hydrocephalus, and agenesis of the corpus callosum. Affected infants also typically have severe growth failure, severe microcephaly, seizures, microphthalmia, and cataracts. Some affected infants have an occipital encephalocele.

Neu-Laxova Syndrome: Rare genetic disorder in which intrauterine growth retardation, polyhydramnios, and an unusually short umbilical cord occur. Typically characterized by severe microcephaly, joint contractures, generalized edema, and abnormalities of the brain and ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.