National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

L1 syndrome


Other Names:
Corpus callosum hypoplasia-retardation-adducted thumbs-spasticity-hydrocephalus syndrome; CRASH syndrome; L1CAM syndrome
Subtypes:
Hydrocephalus due to congenital stenosis of aqueduct of sylvius; Spastic paraplegia 1; X-linked complicated corpus callosum agenesis; Hydrocephalus due to congenital stenosis of aqueduct of sylvius; Spastic paraplegia 1; X-linked complicated corpus callosum agenesis; X-linked complicated spastic paraplegia type 1 See More
L1 syndrome is a mild to severe congenital disorder with hydrocephalus of varying degrees of severity, intellectual disability, spasticity of the legs, and adducted thumbs. It includes several conditions, some more severe than others: X-linked hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS) - the most severe of all; MASA syndrome (intellectual disability, aphasia (delayed speech), spastic paraplegia (shuffling gait), adducted thumbs); SPG1 (X-linked complicated hereditary spastic paraplegia type 1) X-linked complicated corpus callosum agenesis. It is inherited in an X-linked manner; therefore, it only affects males. It is caused by alterations (mutations) in L1CAM gene. The diagnosis is made in males who have the clinical and neurologic findings and a family history consistent with X-linked inheritance and is confirmed by a genetic test showing the L1CAM gene mutation. The treatment involves doing a surgery for the hydrocephalus.[1]
Last updated: 4/24/2015

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Aqueductal stenosis 0002410
Depressivity
Depression
0000716
Gait disturbance
Abnormal gait
Abnormal walk
Impaired gait
[ more ] 		0001288
Global developmental delay 0001263
Headache
Headaches
0002315
Hemiplegia/hemiparesis
Paralysis or weakness of one side of body
0004374
Hydrocephalus
Too much cerebrospinal fluid in the brain
0000238
Hyperreflexia
Increased reflexes
0001347
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Language impairment 0002463
Nausea and vomiting 0002017
Spasticity
Involuntary muscle stiffness, contraction, or spasm
0001257
30%-79% of people have these symptoms
Adducted thumb
Inward turned thumb
0001181
5%-29% of people have these symptoms
Aganglionic megacolon
Enlarged colon lacking nerve cells
0002251
Seizure 0001250
Skeletal muscle atrophy
Muscle degeneration
Muscle wasting
[ more ] 		0003202
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Last updated: 7/1/2020

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
The differential diagnosis is broad. Other hydrocephalus and spastic paraplegia disorders should be ruled out. A pediatric/neurologic/clinical genetics work-up enables diagnosis of the possible individual diseases.
Visit the Orphanet disease page for more information.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.

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  1. Stumpel C & Vos YJ. L1 syndrome. GeneReviews. March 5, 2015; http://www.ncbi.nlm.nih.gov/books/NBK1484/. Accessed 4/24/2015.