Lissencephaly is a family of rare conditions in which the brain fails to develop normally, developing a smooth appearance rather than one which is deeply furrowed with gyri and sulci. The term “lissencephaly” literally means “smooth brain,” referencing the way in which the brains of lissencephalic patients look. Depending on the severity of the condition, the patient may die within a few months of birth, live a relatively normal life, or live into his or her teens but experience severe developmental delays which require constant care and support.
A number of things can lead to lissencephaly. Some patients experience a spontaneous genetic mutation during fetal development which leads to brain abnormalities, while others inherit genetic abnormalities from their parents which lead to lissencephaly. Interruptions in blood flow to the brain during the critical stages of fetal development can also lead to this condition, as can viral infections. The condition is difficult to diagnose with prenatal ultrasounds, and only some forms can be diagnosed with genetic testing.
In classical lissencephaly, also known as Type I lissencephaly, the patient's brain is totally smooth, and the internal structures of the brain are often malformed as well. The patient may also have facial defects and an unusually small head. Within days or weeks or birth, the patient experiences muscle weakness, obvious developmental delays, and seizures, and death usually occurs at less than one year.
Type II lissencephaly is less severe, with the brain having some folds, but not as many as a healthy brain. Patients with this condition can experience seizures and developmental delays along with muscle weakness, and they may live for months or years, depending on the severity their condition. Other types of lissencephaly occur in tandem with other genetic conditions such as Walker-Warburg syndrome and Miller-Dieker syndrome, and also vary considerably in severity.
There is no treatment for this genetic condition, as there is no way to address the malformation of the brain. Care for lissencephalic patients is focused on providing support which can include physical therapy, specialized nutrition, and ventilators. Patients with lissencephaly often die of respiratory problems, and care includes careful monitoring for early signs of respiratory distress. Parents of children with lissencephaly should be aware that because this condition is so variable in nature, it is important to consult a doctor to develop an individualized treatment plan for a patient which takes his or her unique circumstances into account.