A zebrafish model exemplifies the long preclinical period of motor neuron disease

To the Editor, The article ‘Amyotrophic lateral sclerosis: a long preclinical period?’’ is an interesting and thought-provoking review.1 We commend the authors for raising the profile of early embryonic and preclinical stages that are currently poorly explored in amyotrophic lateral sclerosis (ALS) research. In relation to these concepts, we would like to highlight recent, important work on a zebrafish model of ALS that contributes to the concept of preclinical change. Specifically, we have developed a sod1 zebrafish model of ALS/motor neuron disease (MND) and demonstrated that zebrafish, like mice and humans, show hallmark features of ALS, suggesting that the zebrafish provides an excellent model system to study motor neuron disease.2 Additionally, the transparency and ex vivo development of embryos enables one to trace early embryonic changes in disease pathogenesis. As a follow-up to the original study, our further studies have established that the temporal changes in neuronal populations and circuitry were evident from the earliest embryonic …