In our previously published work relating to CLD patients, one subject with a [Hb] of only 69 g/l was given a dose of 0.4 ml/kg producing a ΔCOHb% of 4.7% (Otto, Plumb, Clissold, et al., 2017). Here, GSTM1 is linked to congenital secretory chloride diarrhea 1.