Long-term dietary treatment of tyrosinosis

Recovery after dietary treatment of an infant with features of tyrosinosis.

“…It is well recognized that the phosphaturia may be markedly decreased soon after the start of dietary treatment (Halvorsen, 1967;Gentz et al, 1967;Aronsson et al, 1968), and in our patient this occurred within a few days.…”

“…Enlargement of the kidneys has been noted in several instances (Halvorsen et al, 1966;Perry, 1967;Sass-Kortsak et al, 1967b;Aronsson et al, 1968), and reduction in size reported after treatment. It is presumed that the raised levels of plasma tyrosine (or its metabolites) have a direct effect on the renal substance, particularly on the proximal tubule (Perry et al, 1965;Halvorsen et al, 1966) though glomerular lesions have also been described (Aronsson et al, 1968).…”

“…It is presumed that the raised levels of plasma tyrosine (or its metabolites) have a direct effect on the renal substance, particularly on the proximal tubule (Perry et al, 1965;Halvorsen et al, 1966) though glomerular lesions have also been described (Aronsson et al, 1968). Immature mice fed high tyrosine diets develop large pale kidneys with proximal tubular changes (Halvorsen and Gjessing, 1966), and rats may develop similar abnormalities when fed large amounts of methionine (Klavins, Kinney, and Kaufman, 1963).…”

“…Steatorrhoea in tyrosinosis has been poorly investigated, and though it is generally assumed to be secondary to hepatic cirrhosis, the possibility of a specific intestinal lesion has not been excluded. Though in some cases the rickets has healed on dietary treatment alone, or with small amounts of additional vitamin D (Halvorsen et al, 1966;Aronsson et al, 1968), large doses of vitamin D may be necessary in addition to dietary treatment (Fairney et al, 1968), and occasionally hypercalcaemia has been induced (Gentz, Jagenburg, aud Zetterstrom, 1965). In our patient hypercalcaemia occurred after only a modest increase in dosage (10,000 units daily for 2 weeks), and this may have been related to coincident improvement in intestinal absorption.…”

“…Treatment with a low-tyrosine low-phenylalanine diet is usually followed by rapid and marked improvement in renal function, and subsequent healing of rickets (Halvorsen et al, 1966;Sass-Kortsak et al, 1967c), but its effectiveness in preventing the development of hepatic cirrhosis has not yet been established. In all cases so far reported attempts to terminate the dietary treatment have been followed by rapid clinical and biochemical relapse, and it has been assumed that long-term treatment is therefore essential (Fairney et al, 1968;Aronsson et al, 1968).…”