- A gene for a severe lethal form of X-linked arthrogryposis (X-linked infantile spinal muscular atrophy) maps to human chromosome Xp11.3-q11.2. Kobayashi, H., Baumbach, L., Matise, T.C., Schiavi, A., Greenberg, F., Hoffman, E.P. Hum. Mol. Genet. (1995)