Dandy-walker syndrome is a congenital brain malformation that occurs during the embryonic development affecting a part of the brain known as the cerebellum and the fluid-filled space around it. Dandy-walker syndrome usually affects only the brain of the individual although it can present problems with other parts of the body such as the heart and urogenital tract. The complications that develop from this condition and its treatment are the common cause of death in individuals with the dandy-walker syndrome. The prognosis is based on the severity of this condition and the associated symptoms, however, the multiple congenital abnormalities can shorten the lifespan of these individuals. Dandy-walker syndrome is estimated to affect 1 in 25,000 to 35,000 live births in the U.S.
Causes
Most cases of dandy-walker syndrome are sporadic, meaning it develops in individuals with no history of its prevalence in the family. However, some cases are attributed to the presence of this syndrome in the family indicating an autosomal recessive or X-linked inheritance.
Dandy-walker is associated with several chromosomal abnormalities such as missing or duplications of certain chromosomes and only a few genes are identified to cause this condition. The study suggests that several environmental factors can influence the development of the early stages of the fetus such as exposure to certain substances resulting in birth defects. In addition, maternal diabetes can also contribute to the development of this condition.
Symptoms
The symptoms include the muscle stiffness, partial paralysis of the lower limbs (spastic paraplegia), developmental delays, poor coordination, balance, increased pressure in the skull and sometimes enlarged head. In some cases, the mental retardation is evident; seizures affect 15-30% of the cases along with the respiratory failure. Parts of the cerebellum develop abnormally causing various malformations that are evident in the diagnostic imaging. The central part of the cerebellum may be absent and the side of the cerebellum may be small. The part of the skull that holds the cerebellum and the brainstem may be unusually large presenting problems with the individual’s intellect, mood, movement and other neurological functions. The symptoms associated with the abnormal brain development are usually evident at the birth of the infant or may become evident within the first year. In addition, they can have intellectual difficulties that can be mild or severe and those with normal intelligence may exhibit learning difficulties. In rare cases, hearing and vision problems also feature this syndrome. Abnormalities of other areas of the body can consist of heart defects, fused digits (syndactyly), extra digit (polydactyly) and malformation of the urogenital tract.
Diagnosis
The diagnosis is based on the clinical findings that are evident with the ultrasound, CT and MRI scans. The prenatal diagnosis is also possible that detects the abnormalities from the ultrasound or the fetal imaging.
Treatment
This is focused on treating the associated symptoms that are evident in each individual. A surgery may be necessary to redirect the fluid that surrounds the brain to a region of the body that can absorb it. Other supportive care can include a special education, vocational services and physical therapy. In some cases, genetic counselling may be beneficial to the family of the affected individual.
References
https://rarediseases.org/rare-diseases/dandy-walker-malformation/
https://ghr.nlm.nih.gov/condition/dandy-walker-malformation#diagnosis
http://www.ninds.nih.gov/disorders/dandywalker/dandywalker.htm
