Is hydrocephalus genetically inherited?
It is caused by genetic and non-genetic factors. The most common cause of congenital hydrocephalus are variations ( mutations ) in the L1CAM gene , where there is a narrow passageway between the third and fourth ventricles (aqueductal stenosis).
Who carries the L1CAM gene?
This is because females have a second, intact copy, of the L1CAM gene which is inherited from the father. A female carrier has a 50% chance of transmitting the affected gene to each child. Males with an affected X chromosome have L1 syndrome because the Y chromosome does not contain the L1CAM gene.
What is L1CAM gene?
The L1CAM gene provides instructions for producing the L1 cell adhesion molecule protein (shortened to L1 protein), which is found on the surface of nerve cells (neurons) throughout the nervous system.
What is the most common cause of congenital hydrocephalus?
The most common cause of congenital hydrocephalus is obstruction of the cerebral aqueduct — the long, narrow passageway between the third and fourth ventricle or cavity of the brain. This condition may result from a blockage, infection, hemorrhage, tumor or arachnoid cyst.
What is Masa syndrome?
Disease definition. A X-linked, clinical subtype of L1 syndrome, characterized by mild to moderate intellectual disability, delayed development of speech, hypotonia progressing to spasticity or spastic paraplegia, adducted thumbs, and mild to moderate distension of the cerebral ventricles.
What does the L1 gene do?
L1 is present in developing neurons and plays an important role in guiding new neurons into the correct positions and helping axons grow and make connections with other neurons.
Does hydrocephalus run in families?
Congenital hydrocephalus can run in families. It is thought that congenital hydrocephalus can be caused by genetic defects that can be passed from one or both parents to a child, but the direct links to hereditary disorders are still being investigated.
What does L1 gene do?
Function. L1 is an important protein for the development of the nervous system affecting both cell adhesion and motility.
What causes cerebral aqueduct stenosis?
Aqueductal stenosis is one of the known causes of hydrocephalus and the most common cause of congenital (present at birth) hydrocephalus. It can also be acquired during childhood or adulthood. In some cases, this is due to a brain tumor compression (such as a pineal tumor) surrounding the aqueduct of Sylvius.
What is congenital hydrocephalus?
Congenital hydrocephalus is a buildup of excess cerebrospinal fluid (CSF) in the brain at birth. The extra fluid can increase pressure in the baby’s brain, causing brain damage and mental and physical problems. This condition is rare.
Is the hydrocephalus gene located on the X chromosome?
Hydrocephalus due to congenital stenosis of aqueduct of sylvius is inherited in an X-linked recessive manner. [3] A condition is X-linked if the responsible gene is located on the X chromosome. The X chromosome is one of the two sex chromosomes (the other sex chromosome is the Y chromosome ).
How is hydrocephalus related to recessive inheritance?
Inheritance Inheritance. Hydrocephalus due to congenital stenosis of aqueduct of sylvius is inherited in an X-linked recessive manner. A condition is X-linked if the responsible gene is located on the X chromosome. The X chromosome is one of the two sex chromosomes (the other sex chromosome is the Y chromosome).
What makes a condition X linked in males?
A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. In males, who have only one X chromosome, a mutation in the only copy of the gene in each cell is sufficient to cause the condition.
How is hydrocephalus related to Aqueduct of Sylvius ( HSAS )?
Hydrocephalus due to congenital stenosis of aqueduct of sylvius (HSAS) is a form of L1 syndrome, which is an inherited disorder that primarily affects the nervous system.