Gauge Anomaly associated with the Majorana Fermion in $8k+1$ dimensions
  Using an elementary method, we show that an odd number of Majorana fermions in $8k+1$ dimensions suffer from a gauge anomaly that is analogous to the Witten global gauge anomaly. This anomaly cannot be removed without sacrificing the perturbative gauge invariance. Our construction of higher-dimensional examples ($k geq1$) makes use of the SO(8) instanton on $S^8$. 
Masashi Hayakawa and Hiroshi Suzuki