We show here that iPS cell-induced neurons from a variety of SPAST HSP patients carrying different mutations, including frameshift, missense, and exonic deletion mutations, share common axon pathologies of reduced stabilized microtubules, increased density of axon swellings, reduced microtubule-dependent peroxisome transport, and reduced number of peroxisomes. The gene discussed is SPAST; the disease is hereditary spastic paraplegia.