L1CAM and Aphasia: In addition, Case 33 has adducted thumbs that were very similar to those seen in mental retardation, aphasia, shuffling gait, and adducted thumbs (MASA) syndrome (SPG1), an X-linked spastic paraplegia syndrome that is caused by mutations in theLICAMgene (Jouetet al., 1994;Vitset al., 1994) (Fig. 3).