{"Name":"L1 syndrome","DiseaseID__c":"GARD:0012524","id":12524,"encodedName":"l1-syndrome","IsDeleted":false,"Disease_Name_Full__c":"L1 syndrome","Xref_IDs__c":"716996008; C5779710; MEDGEN:1830362; MONDO:0017140; NBK1484; ORPHA:275543","USA_Estimate__c":null,"No_of_Specialist_Tagsa__c":4,"No_of_ClinGen_records__c":0,"No_of_GeneReviews__c":1,"No_of_HHS_records__c":1,"World_Estimate__c":null,"No_of_HRSA_records__c":0,"Evidence_Based_Score__c":3,"No_of_Disease_Descriptions__c":4,"Disease_Characteristics_Score__c":6,"No_of_Age_at_Onset__c":3,"Description_Source__c":"MONDO:0017140","Disease_Description__c":"A rare, congenital X-linked developmental disorder characterized by hydrocephalus of varying degrees of severity, intellectual deficit, spasticity of the legs, and adducted thumbs. The syndrome represents a spectrum of disorders including: X-linked hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS), MASA syndrome, X-linked complicated hereditary spastic paraplegia type 1, and X-linked complicated corpus callosum agenesis.","GARD_Name__c":"L1 syndrome","GARD_Synonym__c":"corpus callosum hypoplasia-retardation-adducted thumbs-spasticity-hydrocephalus syndrome; crash syndrome; hypoplasia of corpus callosum and mental retardation with adducted thumbs and spasticity and hydrocephalus syndrome; hypoplasia of corpus callosum, intellectual disability, adducted thumbs, spasticity, hydrocephalus syndrome; l1cam syndrome","Curated_Disease_Description_Source__c":"GARD:0012524","Curated_Disease_Description__c":"L1 syndrome describes a group of conditions that primarily affect the nervous system and occur almost exclusively in males. These conditions vary in severity and include, from most severe to least, X-linked hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS), MASA syndrome, spastic paraplegia type 1, and X-linked complicated corpus callosum agenesis. HSAS is an acronym for the characteristic features of the condition: a buildup of fluid in the brain (hydrocephalus) that is often present from before birth, muscle stiffness (spasticity), thumbs that are permanently bent toward the palms (adducted thumbs), and narrowing (stenosis) of a passageway in the brain called the aqueduct of Sylvius. In individuals with HSAS, stenosis of the aqueduct of Sylvius causes hydrocephalus by impeding the flow of cerebrospinal fluid (CSF) out of fluid-filled cavities called ventricles. Individuals with HSAS often have severe intellectual disability and may have seizures. MASA syndrome is also named for the characteristic features of the condition, which are intellectual disability (mental retardation) that can range from mild to moderate, delayed speech (aphasia), spasticity, and adducted thumbs. Individuals with MASA syndrome may have mild enlargement of the ventricles. Spastic paraplegia type 1 is characterized by progressive muscle stiffness (spasticity) and the development of paralysis of the limbs (paraplegia). Affected individuals also have mild to moderate intellectual disability. People with spastic paraplegia type 1 do not usually have major abnormalities in structures of the brain. X-linked complicated corpus callosum agenesis is defined by underdevelopment (hypoplasia) or absence (agenesis) of the tissue that connects the left and right halves of the brain (the corpus callosum). People with this condition can have spastic paraplegia and mild to moderate intellectual disability. The life expectancy of individuals with L1 syndrome varies depending on the severity of the signs and symptoms. Severely affected individuals may survive only a short time after birth, while those with mild features live into adulthood. The conditions that make up L1 syndrome were once thought to be distinct disorders, but since they were found to share a genetic cause, they are now considered to be part of the same syndrome. Family members with L1 syndrome caused by the same mutation may have different forms of the condition.","Curated_USA_Estimate_Source__c":null,"Curated_USA_Estimate__c":null,"Age_at_Onset_Snippet_Text__c":"during Pregnancy, at Birth, and as an Infant","SourceID__c":"ORPHA:275543","Deprecated__c":"No","Disease_Concept_Type__c":"Rare Disease Grouping","MONDO_ID__c":"MONDO:0017140","ORPHANET_ID__c":"ORPHA:275543","Replaced_By_ID__c":null,"Display_Spanish_Disease_Name__c":"Síndrome l1","Spanish_Description_Source__c":"ORPHA:275543","Spanish_Description__c":"Es un trastorno congénito poco frecuente del desarrollo ligado al cromosoma X caracterizado por hidrocefalia con distintos grados de gravedad, déficit intelectual, espasticidad de las piernas, y pulgares en aducción. El síndrome representa un espectro de trastornos como la hidrocefalia ligada al cromosoma X con estenosis del acueducto de Silvio (HSAS), síndrome MASA, paraparesia espástica compleja tipo 1 ligada al cromosoma X, y agenesia del cuerpo calloso compleja ligada al cromosoma X.","Spanish_Disease_Name__c":"síndrome l1","Spanish_GARD_Synonym__c":"síndrome crash; síndrome de hipoplasia del cuerpo calloso-retraso-pulgares en aducción-espasticidad-hidrocefalia; síndrome l1cam","Category_Linearization__c":"ORPHA:93890","icd10_id__c":null,"mesh_id__c":null,"omim_id__c":null,"snomed_id__c":null,"umls_id__c":null,"GARD_Disease__c":[{"Curated_Disease_Description__c":"L1 syndrome describes a group of conditions that primarily affect the nervous system and occur almost exclusively in males. These conditions vary in severity and include, from most severe to least, X-linked hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS), MASA syndrome, spastic paraplegia type 1, and X-linked complicated corpus callosum agenesis. HSAS is an acronym for the characteristic features of the condition: a buildup of fluid in the brain (hydrocephalus) that is often present from before birth, muscle stiffness (spasticity), thumbs that are permanently bent toward the palms (adducted thumbs), and narrowing (stenosis) of a passageway in the brain called the aqueduct of Sylvius. In individuals with HSAS, stenosis of the aqueduct of Sylvius causes hydrocephalus by impeding the flow of cerebrospinal fluid (CSF) out of fluid-filled cavities called ventricles. Individuals with HSAS often have severe intellectual disability and may have seizures. MASA syndrome is also named for the characteristic features of the condition, which are intellectual disability (mental retardation) that can range from mild to moderate, delayed speech (aphasia), spasticity, and adducted thumbs. Individuals with MASA syndrome may have mild enlargement of the ventricles. Spastic paraplegia type 1 is characterized by progressive muscle stiffness (spasticity) and the development of paralysis of the limbs (paraplegia). Affected individuals also have mild to moderate intellectual disability. People with spastic paraplegia type 1 do not usually have major abnormalities in structures of the brain. X-linked complicated corpus callosum agenesis is defined by underdevelopment (hypoplasia) or absence (agenesis) of the tissue that connects the left and right halves of the brain (the corpus callosum). People with this condition can have spastic paraplegia and mild to moderate intellectual disability. The life expectancy of individuals with L1 syndrome varies depending on the severity of the signs and symptoms. Severely affected individuals may survive only a short time after birth, while those with mild features live into adulthood. The conditions that make up L1 syndrome were once thought to be distinct disorders, but since they were found to share a genetic cause, they are now considered to be part of the same syndrome. Family members with L1 syndrome caused by the same mutation may have different forms of the condition.","Curated_Disease_Description_Source__c":"GARD:0012524","GARD_Synonym__c":"corpus callosum hypoplasia-retardation-adducted thumbs-spasticity-hydrocephalus syndrome; crash syndrome; hypoplasia of corpus callosum and mental retardation with adducted thumbs and spasticity and hydrocephalus syndrome; hypoplasia of corpus callosum, intellectual disability, adducted thumbs, spasticity, hydrocephalus syndrome; l1cam syndrome","Name":"L1 syndrome","estimateUsa":""}],"GARD_Disease_Tag__c":[{"Tag_Name__c":"Genetics","Tag_Category__c":"Cause;Disease Category;Specialist","category_description":"Genetic diseases affect the DNA, or genetic instructions, which directs how tissues, organs, and body systems function.","curated_tag_name":"Genetic diseases"},{"Tag_Name__c":"Neurology","Tag_Category__c":"Disease Category;Specialist","category_description":"Neurological diseases affect the brain, spinal cord, cranial nerves, autonomic nerves, or other peripheral nerves.","curated_tag_name":"Neurological diseases"},{"Tag_Name__c":"Congenital Abnormality","Tag_Category__c":"Disease Category","category_description":"Birth defects are structural changes present at birth that can affect almost any part of the body, including how the body looks, works, or both.","curated_tag_name":"Birth defects"},{"Tag_Name__c":"Neurodevelopmental disabilities","Tag_Category__c":"Specialist","curated_tag_name":"Neurodevelopmental disabilities"},{"Tag_Name__c":"Pediatrics","Tag_Category__c":"Specialist"}],"Age_At_Onset__c":[{"Age_At_Onset__c":"Infancy","Provided_By__c":"ORPHA:275543"},{"Age_At_Onset__c":"Neonatal","Provided_By__c":"ORPHA:275543"},{"Age_At_Onset__c":"Antenatal","Provided_By__c":"ORPHA:275543"}],"Diagnosis__c":[{"Type__c":"GTR","Curie__c":"MEDGEN:CN118845"}],"External_Identifier_Disease__c":[{"URL__c":"https://www.ncbi.nlm.nih.gov/books/NBK1484","Source__c":"Gene Review","Xref__c":"NBK1484"},{"URL__c":"https://uts.nlm.nih.gov/uts/umls/concept/C5779710","Source__c":"C5779710","Xref__c":"C5779710"},{"URL__c":"https://www.orpha.net/en/disease/detail/275543","Source__c":"C5779710; MONDO:0017140; ORPHA:275543","Xref__c":"ORPHA:275543"},{"URL__c":"https://www.ncbi.nlm.nih.gov/medgen/?term=1830362","Source__c":"C5779710","Xref__c":"MEDGEN:1830362"},{"URL__c":"http://purl.obolibrary.org/obo/MONDO_0017140","Source__c":"GARD:0012524","Xref__c":"MONDO:0017140"},{"URL__c":"https://medlineplus.gov/genetics/condition/l1-syndrome","Source__c":"GARD:0012524","Xref__c":"https://medlineplus.gov/genetics/condition/l1-syndrome"},{"URL__c":"https://browser.ihtsdotools.org/?perspective=full&conceptId1=716996008","Source__c":"C5779710","Xref__c":"716996008"}],"Inheritance__c":["X-linked recessive"],"GARD_Disease_Feature__c":[{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Frequent (30-79%)","Feature__r":{"HPO_Description__c":"In the resting position, the tip of the thumb is on, or near, the palm, close to the base of the fourth or fifth finger.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001181","HPO_Synonym__c":"Adducted thumbs; Inward turned thumb; Thumb-in-palm deformity; Thumb-in-palm pattern","HPO_Name__c":"Adducted thumb","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001250","HPO_Synonym__c":"Epileptic seizure; Seizures","HPO_Name__c":"Seizure","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Frequently experiencing feelings of being down, miserable, and/or hopeless; struggling to recover from these moods; having a pessimistic outlook on the future; feeling a pervasive sense of shame; having a low self-worth; experiencing thoughts of suicide and engaging in suicidal behavior.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000716","HPO_Synonym__c":"Depression; Depressive episode; Depressivity","HPO_Name__c":"Depression","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0000238","HPO_Synonym__c":"Hydrocephaly; Nonsyndromal hydrocephalus; Too much cerebrospinal fluid in the brain","HPO_Name__c":"Hydrocephalus","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001249","HPO_Synonym__c":"Intellectual disability; Mental deficiency; Mental retardation; Mental retardation, nonspecific; Mental-retardation; Nonprogressive intellectual disability; Nonprogressive mental retardation","HPO_Name__c":"Intellectual disability","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Language impairment is a deficit in comprehension or production of language that includes reduced vocabulary, limited sentence structure, or impairments in written or spoken communication. Language abilities are substantially and quantifiably below age expectations.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002463","HPO_Synonym__c":"Language disorder","HPO_Name__c":"Language impairment","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Nausea is a commonly encountered symptom that has been defined as an unpleasant painless subjective feeling that one will imminently vomit. Vomiting has been defined as the forceful expulsion of the contents of the stomach, duodenum, or jejunum through the oral cavity. While nausea and vomiting are often thought to exist on a temporal continuum, this is not always the case. There are situations when severe nausea may be present without emesis and less frequently, when emesis may be present without preceding nausea.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002017","HPO_Synonym__c":"Nausea and vomiting","HPO_Name__c":"Nausea and vomiting","Feature_System__c":"Digestive System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001257","HPO_Synonym__c":"Involuntary muscle stiffness, contraction, or spasm; Muscle spasticity; Muscular spasticity","HPO_Name__c":"Spasticity","Feature_System__c":"Nervous System; Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"The presence of skeletal muscular atrophy (which is also known as amyotrophy).","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0003202","HPO_Synonym__c":"Amyotrophy; Amyotrophy involving the extremities; Muscle atrophy; Muscle atrophy, neurogenic; Muscle degeneration; Muscle hypotrophy; Muscle wasting; Muscular atrophy; Neurogenic muscle atrophy; Neurogenic muscle atrophy, especially in the lower limbs; Neurogenic muscular atrophy","HPO_Name__c":"Skeletal muscle atrophy","Feature_System__c":"Musculoskeletal System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001347","HPO_Synonym__c":"Increased deep tendon reflexes; Increased reflexes","HPO_Name__c":"Hyperreflexia","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Stenosis of the cerebral aqueduct (also known as the mesencephalic duct, aqueductus mesencephali, or aqueduct of Sylvius), which connects the third cerebral ventricle in the diencephalon to the fourth ventricle, which is between the pons and cerebellum.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002410","HPO_Synonym__c":"Aqueduct of Sylvius stenosis; Aqueduct stenosis; Narrowing of aqueduct of Sylvius","HPO_Name__c":"Aqueductal stenosis","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"The term gait disturbance can refer to any disruption of the ability to walk.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001288","HPO_Synonym__c":"Abnormal gait; Abnormal walk; Difficulty in walking; Gait abnormalities; Gait difficulties; Gait disturbances; Impaired gait; Walking disability","HPO_Name__c":"Gait disturbance","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Loss of strength in the arm, leg, and sometimes face on one side of the body. Hemiplegia refers to a severe or complete loss of strength, whereas hemiparesis refers to a relatively mild loss of strength.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0004374","HPO_Synonym__c":"Paralysis or weakness of one side of body","HPO_Name__c":"Hemiplegia/hemiparesis","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0001263","HPO_Synonym__c":"Delayed cognitive development; Delayed development; Delayed developmental milestones; Delayed intellectual development; Delayed milestones; Delayed psychomotor development; Developmental delay; Developmental delay in early childhood; Developmental delay, global; Developmental retardation; GDD; Lack of psychomotor development; Motor and developmental delay; Motormental retardation; Psychomotor delay; Psychomotor development deficiency; Psychomotor development failure; Psychomotor developmental delay; Retarded development; Retarded mental development; Retarded psychomotor development","HPO_Name__c":"Global developmental delay","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Very frequent (80-99%)","Feature__r":{"HPO_Description__c":"Cephalgia, or pain sensed in various parts of the head, not confined to the area of distribution of any nerve.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002315","HPO_Synonym__c":"Headache; Headaches","HPO_Name__c":"Headache","Feature_System__c":"Nervous System","HPO_Feature_Type__c":"Symptom"}},{"Provided_By__c":"ORPHA:275543","HPO_Frequency__c":"Occasional (5-29%)","Feature__r":{"HPO_Description__c":"An abnormality resulting from a lack of intestinal ganglion cells (i.e., an aganglionic section of bowel) that results in bowel obstruction with enlargement of the colon.","HPO_Feature_URL__c":"https://hpo.jax.org/browse/term/HP:0002251","HPO_Synonym__c":"Enlarged colon lacking nerve cells; Hirschsprung megacolon","HPO_Name__c":"Aganglionic megacolon","Feature_System__c":"Nervous System; Digestive System","HPO_Feature_Type__c":"Symptom"}}],"tags":{"Cause":["Genetics"],"Disease Category":["Genetics","Neurology","Congenital Abnormality"],"Specialist":["Genetics","Neurology","Neurodevelopmental disabilities","Pediatrics"]},"synonyms":["corpus callosum hypoplasia-retardation-adducted thumbs-spasticity-hydrocephalus syndrome"," crash syndrome"," hypoplasia of corpus callosum and mental retardation with adducted thumbs and spasticity and hydrocephalus syndrome"," hypoplasia of corpus callosum, intellectual disability, adducted thumbs, spasticity, hydrocephalus syndrome"," l1cam syndrome"]}