Dandy Walker is often called Dandy Walker Syndrome or Dandy-Walker complex.
The Dandy-Walker complex is best described medically, as a genetically sporadic disorder that occurs in about one in every 25,000 live births, and is mostly commonly found in females. However despite this regular occurence, very little research has been undertaken to investigate this complex issue. We do know however that it is a congenital brain malformation and involves the cerebellum and the fluid filled spaces around it. The lack of research is one of the main reasons for creating this website. At this moment in time we are not sure exactly how we can help, but we know we would like to do something in terms of helping with research.
Dandy Walker Syndrome
A significant element of this syndrome is the partial, or complete absence of the part of the brain located between the two cerebellar hemispheres. There is often an enlargement of the fourth ventricle. There can also be a partial or complete absence of the cerebellar vermis, the posterior midline area of cerebellar cortex responsible for coordination of the axial musculature. There is also likely to be a cyst formation near the internal base of the skull.
Other features include an increase in the size of the fluid spaces surrounding the brain as well as an increase in pressure. The syndrome can appear dramatically or develop unnoticed.
Visible Symptoms
Typical symptoms, which can often occur in early infancy, include slower motor development and progressive enlargement of the skull. In older children, the pressure exercised on the brain can cause effects such as irritability, vomiting and convulsions. There can also be signs such as unsteadiness and lack of muscle coordination. In this situation you would notice jerky movements of the eyes. Other symptoms may include increased head circumference, noticeable bulging at the back of the skull, having problems with the nerves that control the eyes, face and neck, and abnormal breathing patterns.
Dandy-Walker syndrome can also be closely associated with disorders of the central nervous system and can present themselves as malformations of the face, heart, fingers, toes and limbs.
Diagnosis
During pregnancy, pre-natal diagnosis is possible using ultrasound. Dandy walker syndrome is associated with an increased risk for fetal karyotype abnormalities. This type of abnormality is found in the number form or structure of various chromosomes. An amniocentesis can be offered after prenatal diagnosis has taken place.
An amniocentesis, which is also better known as an amniotic fluid test, is a medical procedure and involves the use of fetal infections. A small amount of amniotic fluid, which contains some fetal tissues, is extracted from the amniotic sac surrounding a developing fetus, and then this fetal DNA is examined for genetic abnormalities.
Many people believe that Dandy-Walker is a single syndrome or illness and herein lies a lot of confusion, especially for parents presented with this for the first time. The truth is that several abnormalities of brain development can coexist.
From the limited research that has taken place, three types of Dandy-Walker complexes have been determined:
This is the most severe of the syndromes. In this syndrome the posterior fossa is enlarged and the tentorium is in a high position. There will either be a partial or a complete agenesis(failure to form or develop) of the cerebellar vermis. There is also cystic dilation of the fourth ventricle, which fills the posterior fossa. This often involves hydrocephaly and complications due to associated genetic conditions, such as Spina Bifida.
Dandy Walker Mega Cisterna Magna
In this syndrome the cerebellar vermis and the fourth ventricle are perfectly normal. However the posterior fossa becomes enlarged but this is secondary to the enlarged cisterna. This form is represented by a large accumulation of CSF in the cisterna magna in the posterior fossa.
Dandy Walker Variant
This third type is not as severe as the malformation. This form represents the most wide-ranging set of symptoms and outcomes of Dandy Walker Syndrome. Put simply those who do not fit into the first two syndromes are labelled under the variant syndrome. Here we find the fourth ventricle and the posterior fossa are mildly enlarged. The cerebellar vermis is hypoplastic and has a variably sized cyst space. Patients exhibit hydrocephalus in 25% of cases.
It is only recently that the medical practice has indicated that there are connections among many genetic disorders, both genetic syndromes and genetic diseases. Directly as a result of new genetic research, some of these are highly related in their root cause. This is despite the widely-varying set of medical symptoms that are clinically visible in the disorders.
Dandy-Walker syndrome is one such syndrome and is part of an emerging class of diseases called ciliopathies. Recent research has found that Dandy-Walker syndrome often occurs in patients with PHACES Syndrome.
Treatment
Treatment for individuals with Dandy-Walker syndrome generally consists of treating the associated problems, if in fact it is actually needed. Shunting is a popular treatment whereby a special tube, known as a shunt is placed inside the skull to reduce intracranial pressure and control the swelling.
Treatment may also consist of other more common therapies such as physical therapy, speech therapy or specialized education. Vision teachers may be very helpful if the eyes are affected. It is strongly advised that parents of children with Dandy-Walker syndrome may benefit from genetic counseling if they intend to have more children.
The biggest concern for parents is clearly the wide range of outcomes for the Dandy-Walker syndrome. They can be wide ranging and diverse and can often result in some grim prognosis and mortality rates in younger infants. Neurologists compile mortality statistics who typically deal with worst-case outcomes. As a result Dandy Walker Syndrome is often reflected by a high mortality rate, for both pre, and postnatal in Dandy Walker Syndrome infants.
Children with less severe symptoms may well have normal intellectual development, whereas children with severe malformation could have mental retardation. Longevity depends on the severity of the syndrome and associated malformations.
Dandy Walker Syndrome was named for Walter Dandy and Arthur Earl Walker, two leading scientists.
The Dandy-Walker complex is best described medically, as a genetically sporadic disorder that occurs in about one in every 25,000 live births, and is mostly commonly found in females. However despite this regular occurence, very little research has been undertaken to investigate this complex issue. We do know however that it is a congenital brain malformation and involves the cerebellum and the fluid filled spaces around it. The lack of research is one of the main reasons for creating this website. At this moment in time we are not sure exactly how we can help, but we know we would like to do something in terms of helping with research.
Dandy Walker Syndrome
A significant element of this syndrome is the partial, or complete absence of the part of the brain located between the two cerebellar hemispheres. There is often an enlargement of the fourth ventricle. There can also be a partial or complete absence of the cerebellar vermis, the posterior midline area of cerebellar cortex responsible for coordination of the axial musculature. There is also likely to be a cyst formation near the internal base of the skull.
Other features include an increase in the size of the fluid spaces surrounding the brain as well as an increase in pressure. The syndrome can appear dramatically or develop unnoticed.
Visible Symptoms
Typical symptoms, which can often occur in early infancy, include slower motor development and progressive enlargement of the skull. In older children, the pressure exercised on the brain can cause effects such as irritability, vomiting and convulsions. There can also be signs such as unsteadiness and lack of muscle coordination. In this situation you would notice jerky movements of the eyes. Other symptoms may include increased head circumference, noticeable bulging at the back of the skull, having problems with the nerves that control the eyes, face and neck, and abnormal breathing patterns.
Dandy-Walker syndrome can also be closely associated with disorders of the central nervous system and can present themselves as malformations of the face, heart, fingers, toes and limbs.
Diagnosis
During pregnancy, pre-natal diagnosis is possible using ultrasound. Dandy walker syndrome is associated with an increased risk for fetal karyotype abnormalities. This type of abnormality is found in the number form or structure of various chromosomes. An amniocentesis can be offered after prenatal diagnosis has taken place.
An amniocentesis, which is also better known as an amniotic fluid test, is a medical procedure and involves the use of fetal infections. A small amount of amniotic fluid, which contains some fetal tissues, is extracted from the amniotic sac surrounding a developing fetus, and then this fetal DNA is examined for genetic abnormalities.
Many people believe that Dandy-Walker is a single syndrome or illness and herein lies a lot of confusion, especially for parents presented with this for the first time. The truth is that several abnormalities of brain development can coexist.
From the limited research that has taken place, three types of Dandy-Walker complexes have been determined:
- Dandy Walker Syndrome Malformation
- Dandy Walker Syndrome Mega Cisterna Magna
- Dandy Walker Variant
This is the most severe of the syndromes. In this syndrome the posterior fossa is enlarged and the tentorium is in a high position. There will either be a partial or a complete agenesis(failure to form or develop) of the cerebellar vermis. There is also cystic dilation of the fourth ventricle, which fills the posterior fossa. This often involves hydrocephaly and complications due to associated genetic conditions, such as Spina Bifida.
Dandy Walker Mega Cisterna Magna
In this syndrome the cerebellar vermis and the fourth ventricle are perfectly normal. However the posterior fossa becomes enlarged but this is secondary to the enlarged cisterna. This form is represented by a large accumulation of CSF in the cisterna magna in the posterior fossa.
Dandy Walker Variant
This third type is not as severe as the malformation. This form represents the most wide-ranging set of symptoms and outcomes of Dandy Walker Syndrome. Put simply those who do not fit into the first two syndromes are labelled under the variant syndrome. Here we find the fourth ventricle and the posterior fossa are mildly enlarged. The cerebellar vermis is hypoplastic and has a variably sized cyst space. Patients exhibit hydrocephalus in 25% of cases.
It is only recently that the medical practice has indicated that there are connections among many genetic disorders, both genetic syndromes and genetic diseases. Directly as a result of new genetic research, some of these are highly related in their root cause. This is despite the widely-varying set of medical symptoms that are clinically visible in the disorders.
Dandy-Walker syndrome is one such syndrome and is part of an emerging class of diseases called ciliopathies. Recent research has found that Dandy-Walker syndrome often occurs in patients with PHACES Syndrome.
Treatment
Treatment for individuals with Dandy-Walker syndrome generally consists of treating the associated problems, if in fact it is actually needed. Shunting is a popular treatment whereby a special tube, known as a shunt is placed inside the skull to reduce intracranial pressure and control the swelling.
Treatment may also consist of other more common therapies such as physical therapy, speech therapy or specialized education. Vision teachers may be very helpful if the eyes are affected. It is strongly advised that parents of children with Dandy-Walker syndrome may benefit from genetic counseling if they intend to have more children.
The biggest concern for parents is clearly the wide range of outcomes for the Dandy-Walker syndrome. They can be wide ranging and diverse and can often result in some grim prognosis and mortality rates in younger infants. Neurologists compile mortality statistics who typically deal with worst-case outcomes. As a result Dandy Walker Syndrome is often reflected by a high mortality rate, for both pre, and postnatal in Dandy Walker Syndrome infants.
Children with less severe symptoms may well have normal intellectual development, whereas children with severe malformation could have mental retardation. Longevity depends on the severity of the syndrome and associated malformations.
Brain Illustration
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