Because ADAMTS-4 did not increase glutamate-induced neuronal death in vitro, we hypothesize that ADAMTS-4-dependent decrease of neurotrophic factors released by glial cells around dying motoneurons during ALS may participate in the accelerated neurodegeneration induced by ADAMTS-4 in vivo. The gene discussed is ADAMTS4; the disease is amyotrophic lateral sclerosis.