National Organization for Rare Disorders, Inc.
It is possible that the main title of the report L1 Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
- L1 spectrum
- L1 disease
- 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
- HSAS, aqueductal stenosis, X-linked
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.
National Hydrocephalus Foundation
12413 Centralia Rd.
Lakewood, CA 90715-1653
870 Market Street
San Francisco, CA 94102
National Aphasia Association
350 Seventh Avenue
New York, NY 10007
NIH/National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
NIH/National Institute on Deafness and Other Communication Disorders
31 Center Drive, MSC 2320
Communication Avenue. Bethesda, MD 20892-3456
Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
For a Complete Report
This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to MyD-H, the Dartmouth-Hitchcock patient portal. You must be a registered MyD-H user for the Lebanon, Manchester, or Nashua locations to access this site.
The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.
It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report
This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.
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Last Updated: 8/2/2012
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