A new form of prolonged transient tyrosinemia presenting with severe metabolic acidosis.

Yet another form of tyrosinemia is described, in a young baby who developed metabolic acidosis and ceased to grow when weaned from breast milk onto a higher protein formula. Severe tyrosyluria and mild tyrosinemia cleared on a low-protein diet which also corrected the acidosis. However, restoration of growth required a normal protein intake with very greatly reduced amounts of phenylalanine and tyrosine. The metabolic fault later resolved spontaneously at about 12 months of age. Mental development appears normal and liver disease was never apparent. The patient and her mother both excrete quite large quantities of an unidentified peptide.