What is L1CAM syndrome?

What is L1CAM syndrome?

L1 syndrome Disease definition. A rare, congenital X-linked developmental disorder characterized by hydrocephalus of varying degrees of severity, intellectual deficit, spasticity of the legs, and adducted thumbs.

Is Aqueductal stenosis genetic?

Present in 25% of males with aqueductal stenosis: L1 syndrome is considered the most common genetic form of congenital hydrocephalus and occurs in about 1:30,000 births (33). Transmission of the disease is from mother to sons.

Can hydrocephalus be genetic?

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. However, experts have found a connection between a rare genetic disorder called L1 syndrome and hydrocephalus.

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 gene causes hydrocephalus?

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).

How common is aqueductal stenosis?

Epidemiology. Congenital aqueductal stenosis has an estimated incidence of ~1:5000 births although the reported range varies greatly (3.7:1,000,000 to 1:2000) 5. Rarely it may be inherited in an X-linked recessive manner (Bickers-Adams-Edwards syndrome) 5.

Is hydrocephalus dominant or recessive?

Loss of a single allele prevents formation of the SCO and leads to an autosomal dominant congenital hydrocephalus.

What causes hydrocephalus in pregnancy?

There is no one specific cause of congenital hydrocephalus. However, it may be linked to a genetic defect, or be the result of another disorder such as spina bifida or encephalocele (sac-like protrusions of the brain).

Who affects hydrocephalus?

Hydrocephalus can affect anyone at any age but is most common in infants and older adults. Some of these cases can be associated with abnormalities in the brain and spinal cord during pregnancy. The two major types of hydrocephalus are called communicating hydrocephalus and non-communicating hydrocephalus.

What causes aqueductal stenosis in fetus?

Prenatally, acquired causes are most commonly intrinsic, resulting from infection (aqueduct gliosis/web) or intraventricular hemorrhage. Extrinsic causes are less common in the prenatal period and include tectal plate mass, periaqueductal vascular malformation, or compression from a ventricular diverticulum.

Is hydrocephalus more common in males or females?

Hydrocephalus occurs more frequently in males (64 percent males versus 36 percent females). It occurs in approximately 1 out of every 2,000 live births.

Is there a link between L1CAM and hydrocephalus?

One example with a clear genetic linkage is X-linked hydrocephalus, a rare genetic disorder that occurs in about 1 of 30,000 births (Edwards 1961). X-linked hydrocephalus is characterized by stenosis, or narrowing, of the aqueduct of Sylvius and severe ventriculomegaly. It is part of a group of conditions linked by mutations in the L1CAM gene.

Can a male carry the L1CAM gene?

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. Therefore, in males, all of the gene products are produced from the one affected L1CAM gene.

How are L1CAM mutations inherited through the maternal line?

L1CAM mutations can occur in a person through a spontaneous, new (de novo) mutation or by inheriting the mutation from his or her mother. There are no reported cases of inheritance through the father. L1CAM mutations are inherited through the maternal line because L1CAM is located on the X chromosome (X-linked inheritance).

Where are L1 cams found in the nervous system?

The L1 family of CAMs is found primarily in the developing nervous system. These membrane glycoproteins guide neurite outgrowth, neuronal cell migration, fasciculation, and the development of the cortical spinal tract. L1 syndrome results from various mutations in the gene encoding the neuronal CAM L1.