Mouse Genome Informatics
ot
    L1camtm1Mtei/Y
either: (involves: 129/Sv * C57BL/6J) or (involves: 129/Sv * 129S/SvEv)
Key:
phenotype observed in females
phenotype observed in males
N normal phenotype
growth/size/body
• mutant mice are smaller than wild-type

behavior/neurological
• mutants have trouble using their hindlimbs and often stumble (ie. when walking over a metal grid)
• mutants show no reaction to being touched lightly on the flank or to a needle poke
• hind legs of mutants appear weak and uncoordinated
• when placed on a metal grid which is then inverted, mutants often lose their grip (11/17) and fall with a average time to falling 17.7 seconds compared to wild-type (1 animal fell after 56 seconds)
• mutants placed on a warm plate display a delay in jumping off the plate compared to wild-type

nervous system
• Background Sensitivity: a high percentage of male mutants on the C57BL/6J background displayed enlarged brain ventricles; on a 129/SvEv background, no animals had enlarged ventricles
• in mutants, many non-myelinating Schwann cells (87%) form additional processes, protruding in the endoneurial space not associated with axons and covered by a basal lamina; no wild-type non-myelinating Schwann cells have such processes
• size is reduced in mutants
• when cultured on poly-L-lysine + L1 substrate, mutant cerebellar neurons show no outgrowth whereas wild-type neurons grow vigorously
• cerebellar explants from mutant mice show reduced fasciculation compared to wild-type

vision/eye
• eyes of mutants are set further back in their sockets

integument
• mutants show no reaction to being touched lightly on the flank or to a needle poke
• mutants placed on a warm plate display a delay in jumping off the plate compared to wild-type

Mouse Models of Human Disease
OMIM IDRef(s)
MASA Syndrome 303350 J:43838