Sir.—Although neonatal tetany due to phosphorus overload has long been recognized, Venkataraman and colleagues1 emphasized in their article in an issue of AJDC that this type of neonatal tetany was observed in infants fed "humanized" cow's milk for
mula and that hyperparathyroidism was associated with continued phosphorus overload.
Patient Reports.—We recently examined three children with late neonatal tetany, all of whom were healthy, full-term infants; they were fed exclusively on cow's milk formula from birth and brought to Asahikawa Medical College Hospital, Asahikawa, Japan, with tetany at 5 to 10 days of age. Details of feeding and laboratory data are shown in Table 1. Low serum calcium and magnesium and high phosphorus levels were found, characteristic of late neonatal hypocalcemic tetany. The parathyroid hormone level was markedly elevated in one patient, while in the other two patients the value remained within the normal range. All infants were