Two candidates, neurofilament and p75 neurotrophin receptor, are being investigated as pharmacological markers in conjunction with amyotrophic lateral sclerosis clinical trials.14-16 RNA biomarkers are also of interest as amyotrophic lateral sclerosis biomarkers (e.g. Joilin et al.,17 Zhu et al.,18 Shen et al. 19 and Grima et al.20) and, in combination with neurofilament, may have promise in survival prognostication.12 A recent study has demonstrated the potential of HDGFL2, a cryptic neoepitope, as a marker of pre-symptomatic amyotrophic lateral sclerosis.21 The gene discussed is HDGFL2; the disease is amyotrophic lateral sclerosis.