Schizencephaly is a condition involving the abnormal formation of the brain. It occurs during fetal development and, while the symptoms can be treated, there is no cure. The severity of the symptoms and the life expectancy of the individual can vary widely.
Definition & Facts
Schizencephaly occurs when the brain develops clefts, or cracks, in the cerebral cortex. If these cerebral clefts occur on only one side of the brain, this is called unilateral schizencephaly. If they occur on both sides of the brain, it is bilateral schizencephaly. Schizencephaly occurs very rarely. It has been estimated that it is found in about 1.5 out of every 100,000 live births.
There does not appear to be any gender difference in the frequency with which it occurs. Approximately 70 percent of cerebral clefts are found in the frontal lobes and parietal lobes of the brain, although if they are large they may extend into the occipital lobes and temporal lobes. Patients with unilateral schizencephaly often survive well into adulthood while those with the bilateral form are unlikely to survive past the age of 20.
Symptoms & Complaints
Besides seizures, individuals with both the unilateral and bilateral forms of this disorder may have a small head (microcephaly), some degree of paralysis, and generally poor muscle development. Some may develop an accumulation of fluid in the brain called hydrocephalus.
The unilateral form of the condition is less severe than the bilateral type. It is usually characterized by what are called closed lip clefts in the brain. These are clefts in which the sides touch, leaving little open space between them. Individuals with this type often have paralysis on one side of the body and frequently display average intelligence.
Bilateral schizencephaly is the more severe form and most often occurs as open lip clefts. These clefts have walls that do not touch, leaving a cavity that is filled with cerebrospinal fluid. Individuals with this form may suffer more extensive cognitive and physical developmental delays, including language disorders and speech disorders.
The underlying cause of schizencephaly is that the neurons of the brain fail to properly distribute themselves during early fetal development, leaving the characteristic cracks in the grey matter of the cortex. The reason for this developmental failure is still not fully known.
Possible causes that are being studied include fetal strokes, genetic mutations, and environmental factors. Fetal strokes that occur before 13 weeks of pregnancy seem to be associated with some cases of the disorder. These strokes can be caused by a number of factors, including a deficiency of folic acid.
Factors that affect the fetal environment are also suspected causes. The disorder seems to occur with greater frequency in infants that are abandoned or placed for adoption, and these infants are also more likely to have been exposed to drugs or alcohol during fetal development. At this time there is no direct link between maternal use of any particular substance and schizencephaly, but researchers are exploring this possibility.
It was once thought that there was no genetic component to the condition, but further research has suggested that there may be a familial thread in some cases. There is still much work to be done before any conclusions can be drawn about the causes of this disorder.
Diagnosis & Tests
Schizencephaly can sometimes be detected with prenatal ultrasound. The open lip type, which is usually the more serious type, is often very visible while the closed lip type is much more difficult to see.
The most accurate diagnosis is made through a magnetic resonance imaging (MRI). The images produced allow for a clear recognition of both the open and closed lip types and can determine if the clefts are unilateral or bilateral.
If the disorder is not detected prenatally, it is most often diagnosed by a doctor very early in the child’s life. The cognitive deficits and physical disabilities tend to be obvious enough that the child’s parents realize something is wrong and seek a diagnosis. Unfortunately, schizencephaly is so rare that it is often misdiagnosed early on, and it is only after an MRI is finally performed that the true condition is identified.
Treatment & Therapy
There is no cure for schizencephaly, but it is also not degenerative. Therapy and treatments are designed to manage the symptoms and preserve the level of functionality that each individual is capable of. Treatment is most critical during the period from birth to three years of age. The most common symptoms, seizures, are controlled by medication, although it may take some time and experimentation to find the right combination of drugs to best help each patient.
The muscle weakness that is typical of schizencephaly can be treated with physical therapy. Although therapy can preserve muscle strength somewhat, some people may still need to use a wheelchair; others may do well with a walker, braces, or other mobility aids.
Skeletal disorders may need to be controlled with braces or even orthopedic surgery. If a person suffers frequent hip dislocations, he or she may require surgery. Scoliosis may also require surgery, although less severe forms can be treated with braces. In cases where hydrocephaly has developed, a cerebral shunt will need to be placed in the brain to drain the excess fluid and prevent potentially devastating damage to the brain tissue.
Prevention & Prophylaxis
Extensive genetic testing may help identify any familial tendency for schizencephaly, especially if one child has already been born with the disorder.