Dandy-Walker Syndrome

First described in 1887, named by the German Psychiatrist Clemens Ernst Benda after the American neurosurgeons, Walter Dandy and Arthur Earl Walker, the Dandy-Walker Syndrome or DWM is basically an abnormal brain formation where the cerebellar vermis, i.e, the part joining the two hemispheres of the cerebellar hemispheres does not form. Further, there is the malfunctioning of the fourth ventricle leading to problems in proper passage of the cerebrospinal fluid in which the brain floats and thus, causes ‘Hydrocephalus’ or enlarging of the brain. The posterior fossa or the base of the skull is enlarged as a result.  The cerebrospinal fluid produced by the choroid plexus travels from the lateral ventricles to the third ventricle and finally drains after passing through the fourth ventricle. In this condition, since the normal flow of the fluid is disrupted, the result is too much of pressure in the brain that often causes a lot of impairment especially in the nervous system.

The prominent and common symptoms are obviously increased head size, followed by vomiting, seizures, downward deviation of eyes, irritability, and excessive sleepiness. The less common symptoms, on the other hand, include eye abnormalities, congenital heart disease, and tumours, skeletal abnormalities. More severe malfunctioning include agenesis of the corpus callosum which is basically the absence of the corpus callosum and occipital encephalocele where there is sac-like protrusions of parts of the brain.

This syndrome can be attributed to quite a few abnormalities:

• Malfunctioning and blockage of cell division during embryonic development especially the fifth week when the cerebellum form.
• Chromosomal abnormality takes the form of trisomy or one additional chromosome. This condition has been found to result from trisomy 13, trisomy 18, and trisomy 9. One most common complication is partial presence or duplication of 3q.
• Exposure or usage of warfarin during pregnancy also contributes to this syndrome.

Diagnosis of this syndrome is easily accessible. The main symptoms include an enlarged fourth ventricle, absence of cerebellar vermis.

• Prenatal ultrasound as early as 14 weeks can reveal the presence of this abnormal.
• CT scans and MRI are other effective options.

Since the cerebellum has a crucial role to play in motor coordination and movement, this syndrome often causes developmental delay, learning disabilities among the common. Mood fluctuations including mania and depressive episodes are common. Bipolar Disorder and Obsessive-Compulsive Disorder have been found co-morbid with this syndrome. This makes sense because this condition affects the orbitofrontal cortex, dorsolateral prefrontal cortex, and medial frontal cortex- all seats for mood disorders. Psychotic symptoms are commonly found in patients diagnosed with this. Since the base of the brain is affected, therefore, sleep regulation faces a hindrance. There is irritability and people are often found to be borderline intellectually functionable. Paranoid delusions and other psychotic schizophrenic like symptoms have also been reported.

Treatment includes inserting a special tube to absorb and direct the cerebrospinal fluid to other parts of the body preventing accumulation in the fourth ventricle in case of hydrocephalus. Since there is a problem with muscle coordination, physical therapy is recommended. In order to overcome the difficulties of intellectual functioning, special educators are required. In fact, families of people with this syndrome are sent for genetic counseling.