UniProtSummary | Function:Celladhesionmoleculewithanimportantroleinthedevelopmentofthenervoussystem.Involvedinneuron-neuronadhesion,neuritefasciculation,outgrowthofneurites,etc.Bindstoaxoninonneurons. Subcellularlocation:Cellmembrane;Single-passtypeImembraneprotein. Involvementindisease:DefectsinL1CAMarethecauseofhydrocephalusduetostenosisoftheaqueductofSylvius(HSAS)[MIM:307000].Hydrocephalusisaconditioninwhichabnormalaccumulationofcerebrospinalfluidinthebraincausesincreasedintracranialpressureinsidetheskull.Thisisusuallyduetoblockageofcerebrospinalfluidoutflowinthebrainventriclesorinthesubarachnoidspaceatthebaseofthebrain.Inchildrenistypicallycharacterizedbyenlargementofthehead,prominenceoftheforehead,brainatrophy,mentaldeterioration,andconvulsions.Inadultsthesyndromeincludesincontinence,imbalance,anddementia.HSASischaracterizedbymentalretardationandenlargedbrainventricles. DefectsinL1CAMarethecauseofmentalretardation-aphasia-shufflinggait-adductedthumbssyndrome(MASA)[MIM:303350];alsoknownascorpuscallosumhypoplasia,psychomotorretardation,adductedthumbs,spasticparaparesis,andhydrocephalusorCRASHsyndrome.MASAisanX-linkedrecessivesyndromewithahighlyvariableclinicalspectrum.Mainclinicalfeaturesincludespasticityandhyperreflexiaoflowerlimbs,shufflinggait,mentalretardation,aphasiaandadductedthumbs.Thefeaturesofspasticityhavebeenreferredtoascomplicatedspasticparaplegiatype1(SPG1).Somepatientsmanifestcorpuscallosumhypoplasiaandhydrocephalus.Inter-andintrafamilialvariABIlityisverywide,suchthatpatientswithhydrocephalus,MASA,SPG1,andagenesisofcorpuscallosumcanbepresentwithinthesamefamily. DefectsinL1CAMarethecauseofspasticparaplegiaX-linkedtype1(SPG1)[MIM:303350].Spasticparaplegiaisadegenerativespinalcorddisordercharacterizedbyaslow,gradual,progressiveweaknessandspasticityofthelowerlimbs. DefectsinL1CAMmaycontributetoHirschsprungdisease(HSCR)[MIM:142623].ItmaydosobymodifyingtheeffectsofaHirschsprungdisease-associatedgenetocauseintestinalaganglionosis. DefectsinL1CAMareacauseofpartialagenesisofthecorpuscallosum[MIM:304100];aX-linkeddisorder. Sequencesimilarities:Belongstotheimmunoglobulinsuperfamily.L1/neurofascin/NgCAMfamily. Contains5fibronectintype-IIIdomains. Contains6Ig-likeC2-type(immunoglobulin-like)domains. |