RT Journal Article SR Electronic T1 Japanese amyotrophic lateral sclerosis patients with GGGGCC hexanucleotide repeat expansion in C9ORF72 JF Journal of Neurology, Neurosurgery & Psychiatry JO J Neurol Neurosurg Psychiatry FD BMJ Publishing Group Ltd SP 398 OP 401 DO 10.1136/jnnp-2012-302272 VO 84 IS 4 A1 Takuya Konno A1 Atsushi Shiga A1 Akira Tsujino A1 Akihiro Sugai A1 Taisuke Kato A1 Kazuaki Kanai A1 Akio Yokoseki A1 Hiroto Eguchi A1 Satoshi Kuwabara A1 Masatoyo Nishizawa A1 Hitoshi Takahashi A1 Osamu Onodera YR 2013 UL http://jnnp.bmj.com/content/84/4/398.abstract AB Background A GGGGCC hexanucleotide repeat expansion in C9ORF72 occurs on a chromosome 9p21 locus that is linked with frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) in white populations. The diseases resulting from this expansion are referred to as ‘c9FTD/ALS’. It has been suggested that c9FTD/ALS arose from a single founder. However, the existence of c9FTD/ALS in non-white populations has not been evaluated. Results We found two index familial ALS (FALS) patients with c9FTD/ALS in the Japanese population. The frequency of c9FTD/ALS was 3.4% (2/58 cases) in FALS. No patients with sporadic ALS (n=110) or control individuals (n=180) had the expansion. Neuropathological findings of an autopsy case were indistinguishable from those of white patients. Although the frequency of risk alleles identified in white subjects is low in Japanese, one patient had all 20 risk alleles and the other had all but one. The estimated haplotype indicated that the repeat expansion in these patients was located on the chromosome with the risk haplotype identified in white subjects. Conclusions C9ORF72 repeat expansions were present in a Japanese cohort of ALS patients, but they were rare. Intriguingly, Japanese patients appear to carry the same risk haplotype identified in white populations.