About hydrocephalus, internal dandy-walker type
What is hydrocephalus, internal dandy-walker type?
Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and behavior. The 4th ventricle is a space around the cerebellum that channels fluid from inside to around the outside of the brain. DWM is characterized by underdevelopment (small size and abnormal position) of the middle part of the cerebellum known as the cerebellar vermis, cystic enlargement of the 4th ventricle and enlargement of the base of the skull (posterior fossa). DWM is sometimes (20-80%) associated with hydrocephalus, in which blockage of the normal flow of spinal fluid leads to excessive amounts of fluid accumulating in and around the brain. This leads to abnormally high pressure within the skull and swelling of the head, and can lead to neurological impairment.
What are the symptoms for hydrocephalus, internal dandy-walker type?
The symptoms of Coffin-Lowry syndrome tend to be more severe in males, although symptoms in affected females can range from none to the same severity seen in males. The characteristic facial features seen in affected males become more easily identifiable in late childhood and adulthood. The face is characterized by a prominent forehead and eyebrows, narrowing of both temples, scarce hair on the scalp, thickened eyebrow ridges, downslanting eyelid slits, wide-set eyes, thickened upper eyelids, a broad nasal bridge with a thick dividing cartilage (septum), thick prominent lips, an open mouth, prominent chin and ears.
Limb abnormalities may include large soft hands with double-jointed thick fingers that taper toward the tips, an unusual prominent transverse crease (hypothenar) and a shortened big toe. In males, the skin is loose and may stretch easily. Many bone abnormalities may also occur such as thickening of facial bones, shortening of the long bones, and pointed or sunken breast bone. Abnormal front-to-back and side-to-side curvature of the spine may also be present (kyphosis and scoliosis) and progresses with age. Affected individuals usually have short stature. A smaller than average head size (microcephaly) and dental abnormalities are common. Hearing loss is sometimes associated with Coffin-Lowry syndrome. In rare cases, Vision loss may occur. Heart problems may be present and can be life threatening.
Affected males may have severe to profound intellectual disability. Intelligence in affected females ranges from normal to profound intellectual disability. Severely affected children may have no speech development.
Some affected individuals experience episodes of brief collapse without loss of consciousness (drop attacks) that occur following an unexpected noise or emotional event.
What are the causes for hydrocephalus, internal dandy-walker type?
Coffin-Lowry syndrome is caused by changes (mutations) in the RPS6KA3 gene on the X chromosome. Some individuals with Coffin-Lowry syndrome do not have a detectable mutation in the RPS6KA3 gene.
Coffin-Lowry syndrome is inherited in an X-linked dominant pattern. About 70-80% of those affected have no family history of the condition. Males with a RPS6KA3 gene mutation will be affected with Coffin-Lowry syndrome and females with a RPS6KA32 gene mutation have a high risk for developmental delay and mild physical symptoms of the disease.
What are the treatments for hydrocephalus, internal dandy-walker type?
Treatment for Coffin-Lowry syndrome is symptomatic and supportive. Affected individuals should have regular cardiac, hearing and visual examinations. Patients should be monitored for progressive kyphoscoliosis which can be life threatening if the cardiorespiratory system becomes compromised. Antiepileptic medications such as clonazepam may be used to treat drop attacks.
Genetic counseling is recommended for families.
What are the risk factors for hydrocephalus, internal dandy-walker type?
Coffin-Lowry syndrome affects as many males as females. However, symptoms may be more severe in males.