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NORD is very grateful to Joseph Kim, NORD Editorial Intern from the University of Notre Dame, and Connie TRM Schrander-Stumpel, MD, PhD, Department of Clinical Genetics and School for Oncology & Developmental Biology (GROW), MaastrichtUMC+, Maastricht, the Netherlands, for assistance in the preparation of this report.
Synonyms of L1 Syndrome
- HSAS, aqueductal stenosis, X-linked
- L1 disease
- L1 spectrum
- MASA syndrome
- SPG1 (X-linked complicated hereditary spastic paraplegia type 1)
- X-linked corpus callosum agenesis
- X-linked hydrocephalus with stenosis of the aqueduct of sylvius
- No subdivisions found.
L1 syndrome is an inherited, X-linked disorder occurring in males that primarily affects the nervous system. The disease is mainly characterized by hydrocephalus (increased fluid in the center of the brain), spasticity of the lower limbs (muscle stiffness), adducted thumbs (clasped towards the palm), aphasia (difficulty with speaking), seizures, and agenesis of the corpus callosum (underdeveloped or absent connecting tissue between the left and right hemispheres of the brain). Affected individuals have intellectual disability in the mild to moderate range. L1 syndrome is caused by abnormalities (mutations) in the L1CAM gene, which affects about 1 in 30,000 males.
The acronym CRASH (corpus callosum hypoplasia, retardation, adducted thumbs, spastic paraparesis and hydrocephalus) syndrome was originally proposed in 1995 by Dr. Erik Fransen to describe L1 syndrome but is no longer used.
L1 Syndrome Resources
(Please note that some of these organizations may provide information concerning certain conditions potentially associated with this disorder [e.g., mental retardation, aphasia, hydrocephalus, etc.].)
NORD Member Organizations:
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