- Tissue-specific somatic mosaicism in spinal and bulbar muscular atrophy is dependent on CAG-repeat length and androgen receptor--gene expression level. Tanaka, F., Reeves, M.F., Ito, Y., Matsumoto, M., Li, M., Miwa, S., Inukai, A., Yamamoto, M., Doyu, M., Yoshida, M., Hashizume, Y., Terao, S., Mitsuma, T., Sobue, G. Am. J. Hum. Genet. (1999)