Japanese amyotrophic lateral sclerosis patient with learning disabilities with a deletion mutation in the C-terminal of the FUS/TLS gene

Abstract

We report a 19-year-old Japanese man with a heterozygous deletion mutation (c.1485delA, p.G497AfsX527) in the fused in sarcoma/translated in liposarcoma gene. His mother and aunt were diagnosed with amyotrophic lateral sclerosis. He and his mother had learning disabilities. He noted muscle weakness of the right arm at age 18 years and 9 months. His respiratory function worsened rapidly, and he died of respiratory failure 11 months after onset. To date, the fused in sarcoma/translated in liposarcoma c.1485delA mutation has only been reported in three patients in a Caucasian family, and all those patients had a short disease course (12-18 months) and learning disabilities or slowness in school, similar to our patients. Thus, the fused in sarcoma/translated in liposarcoma c.1485delA mutation might cause a rapid disease course and affect the learning function. This is the first non-Caucasian patient with a heterozygous mutation, c.1485delA, in the fused in sarcoma/translated in liposarcoma gene.