108
January 1978 The Journal o f P E D I A T R I C S
Tyrosinemia associated with perinatal infection with cytomegalovirus A premature infant presented with elevated concentrations of tyrosine in blood and urine, evidence of hepatocellular damage, demineralization of the bones, and a renal Fanconi syndrome. This is the clinical picture found in hereditary tyrosinemia. The infant also had a perinatal infection with cytomegalovirus. J . T h o e n e , M . D . , * L. S w e e t m a n , P h . D . , L a Jolla, Calif., T. S h a f a i , M . D . , P h . D . , Riverside, Calif., N . K e n n a w a y , D. Phil., J . F e l l m a n , P h . D . , Portland, Ore.,
and W . N y h a n , M . D . , P h . D . ,
L a Jolla, Calif.
TYROSINEMIA iS a syndrome which usually presents in the neonatal period with altered metabolism of tyrosine, evidence of hepatocellular damage, and a renal Fanconi syndrome. In most instances this disorder appears to be genetically determined? Evidence supporting an autosomal recessive transmission of tyrosinemia with this clinical picture has come from the study of a French-Canadian isolate. ~ However, abnormalities of tyrosine metabolism have been reported in adults with a variety of liver diseases 3 and in infants with neonatal hepatitis.' There is another form of inherited tyrosinemia in which tyrosine aminotransferase is deficient? It is the purpose of this communication to present the case report of a premature infant who presented at 3 months of age with the typical picture of tyrosinemia, including elevated plasma concentrations of tyrosine, abnormal conversion of phenylalanine to tyrosine, glycosuria, aminoaciduria, abnormal tests of liver function, and was shown to have infection with cytomegalovirus. Perinatal infection with From The Department of Pediatrics, University of California, San Diego, The Department of Pediatrics, Riverside General Hospital, University Medical Center, and The Division of Medical Genetics and Department of Biochemistry, University of Oregon, Health Sciences Center. Aided by United States Public Health Service Grants No. AM00321 and AM17906, from the National Institute of Arthritis, Metabolism, and Digestive Diseases, National Institutes of Health. *Reprint address: Department of Pediatrics, University of Michigan Medical Center, R6048 Kresge 1!, Ann Arbor, MI 48104.
Vol. 92, No. 1, pp. 108-112
C M V can apparently cause abnormalities in metabolism which closely mimic hereditary tyrosinemia. CASE REPORT
Patient R.D., a male infant who was born after approximately 28 weeks of gestation to unrelated Caucasian parents, was referred at 3 months of age because reducing substance was found in the urine. The birth weight was 795 gin, and the initial physical examination was unremarkable. He developed respiratory distress syndrome which required a ventilator for 3% weeks. Abbreviations used CMV: cytomegalovirus SGOT: serum glutamic oxalacetic transaminase SGPT: serum glutamic pyruvic transaminase PHPLA: p-hydroxyphenyllactic acid This was followed by intermettent apnea for 2 months. No hepatomegaly was noted. The serum concentration of bilirubin rose to 7.6 mg/dl, and he was treated with phototherapy. After an initial decline in the concentration of bilirubin the infant was found at 8 weeks of age to have a total bilirubin concentration of 8.1 mg/dl with 4.6 mg/dl direct. The liver was palpable 3 cm below the right costal margin. The hepatitis B surface antigen test was negative. The SGOT was 226 IU, the SGPT 58 IU, and the alkaline phosphatase 1,700 IU. At t2 weeks Of age he weighed 2,116 gm. The liver was still enlarged and liver function remained abnormal. The bilirubin had increased to 10.6/5.3 mg/dl. He had intermittent apnea. Alpha~-antitrypsin levels were in the normal range. At this time screening of urine for metabolic disease revealed 2 + reducing substance and 4 + nitrosonaphthol, indicating an elevation of urinary phenolic acids. The plasma concentration of tyrosine was 7.09 mg/dl (nl 0.5 to 1.8
Volume 92 Number 1
Tyrosinemia with C M V infection
10 9
2400
WEIGHT
2300
2200
i
i
i
i
i
i
f
i
i
,.,
3.0 DIETARY PROTEIN
2.0
( glKg/day ) 1.0
o 16o DIETARY CALORIES
140
callKg/doy 120
100'
t
4.0
5.0 PLASMA TYROSINE
2.0
mgldl 1.0
THERAPY
i
URINARY NITROSONAPHTHOL BILIRUBIN ALKALINE PHOSPHATASE
Vii.
+
+ + + +
+
-i- +
Z0/2.7
6.2/2.0
I
1780 O'
Ascorbic A c i d l O 0 m g / d 0 y I D 5000 u. per day + TR
5.8/I.5
' rO
' 15
+
4 . 9 / I . 5 5.1/I.5
1428 5
44-
187 2'0
2'5
' 50
3'5
4'0
HOSPITAL DAY
Fig. 1. Graphic summary o f the hospital course. mg/dl) and the concentration of methionine with 0.62 mg/dl (nl 0.13 to 0.61). He was subsequently transferred to University Hospital, San Diego. On admission, the infant was a small, malnourished Caucasian male with greenish skin. The sclerae were icteric. He weighed 2,280 gm. A smooth liver edge was palpable 3 cm below the right costal margin. Physical examination was otherwise unremarkable. Electrolyte analysis and complete blood count were within normal limitsl The serum concentration of bilirubin was 7.0/2.7 mg/dl. The SGOT was 166 IU; the SGPT was 48 IU; the alkaline phosphatase 1,780 IU; and the concentration of NH3 79. The serum concentration of Ca*+ was 8.9, PO4 3.2, blood Urea nitrogen 3, and glucose 36 mg/dl. Titers for rubella and herpes were each < 1:8 on two occasions. The titer to glycine extracted
CMV antigen was 1:64. A quantitative VDRL and adsorbed fluorescent treponemal antibody were negative. The IgM at 4 months of age was 46 mg/dl. Roentgenograms of the long bones demonstrated severe demineralization and a pathologic fracture of the left distal ulna. Treatment was begun with vitamin D in a dose of 5;000 U per day, and evaluation of the abnormality in tyrosine metabolism was begun. Three separate urine cultures were positive for cytomegalovirus. By this time the serum concentration o f bilirubin had fallen to 5.1/1.5 mg/dl, the SGOT was 106 IU, and the alkaline phosphatase was 187 IU. He was discharged to the care o f his parents, feeding well, and gaining weight. At 7 months the patient developed an acute bronchopneumonia, rapidly became comatose, and died. An autopsy showed
1 10
Thoene et al.
The Journal of Pediatrics January 1978 Table I. Concentrations of amino acids and organic acids in the blood and urine
I0.0
9.0
Plasma (mg/dl)
Hospital day Tyrosine Methionine
8.0
1 2 5 8 l0 13 14 21
7.0
6.0
\
5,0
E
1.09
Urine tyrosine (rag~rag ereatinine)
0.38 0.038
3.94
0.37
0.32
0.22
0.315
Urine PHPLA (l~mol/mg creatinine) 2.72 2,90 6,70 13,60 14.80 3.80 2.00
4.0 Table II. Activity of hepatic p-hydroxyphenylpyruvate hydroxyiase and tyrosine aminotransferase in the patient and normal controls
7.0 2.0
p-Hydroxyphenylpyruvate hydroxylase
1.0 9
i
0
2
i
46 HOURS
i
8
extensive hepatic cirrhosis and fibrosis. There were multinucleated giant cells in liver, kidney, and lung, consistent with a systemic viremia. Cytomegalovirus inclusion particles were not demonstrated. METHODS
pmole/mg protein/hr
l'O
Fig. 2. Phenylalanine tolerance test performed by the oral administration of 100 mg/kg of L-phenylalanine on hospital day 23 (e plasma phenylalanine, oplasma tyrosine).
AND RESULTS
Samples of plasma and urine for amino acid analysis were kept on ice until deproteinized with 4% sulfosalicylic acid, and analyzed on a Beckman 120 amino acid analyzer# P-Hydroxyphenyllactic acid was quantitated by automatic spectrophotometric titration of urinary acids eluted from a liquid partitition chromatographic column.' Identification of urinary organic acids was done by gas chromatography-mass spectrometry of the trimethylsilyl derivatives.' Assay of hepatic p-hydroxyphenylpyruvic acid hydroxylase and tyrosine aminotransferase were performed as previously described. 8, 9 The infant was given a diet which supplied 105 calories/kg/day and 1 g m / k g / d a y of protein, consisting of Enfamil, Polycose, and medium-chain triglycerides, After the institution of this diet, the plasma concentration of
Tyrosine aminotransferase
Patient R.D. Control 1 Control 2
0.097 0.40 0.48
0.46 0.57 0.60
tyrosine was found to be 1.09 mg/dl and the urinary nitrosonaphthol was 1+. After nine days of this diet, he was given Enfamil ad lib and injested approximately 3 gm/kg/day of protein and 105 calories/kg/day. The plasma concentration of tyrosine rose rapidly to 3.94 rag/d1, and the urinary nitrosonapthol rose to 3 ~ (Fig 1). Quantitation of the urinary organic acids showed an elevation of PHPLA from 2.72 ~tmol/mg creatinine on admission to 14.8/~mol/mg creatinine on day 10 (Table I), when he was receiving 3 gm/kg of dietary protein. There was a generalized aminoaciduria. The urinary excretion of tyrosine was 0.315 mg/mg creatinine on day 10. Plasma concentrations of amino acids other than tyrosine were normal. The concentration of methionine was not elevated. A-Aminolevulinic acid was not found in the urine. A diet restricted in protein to 1.0 g m / k g / d a y was reinstituted (Fig. 1) and the plasma concentration of tyrosine again fell rapidly to normal. A phenylalaninetyrosine conversion test was performed on day 23 by administering a load of 100 mg/kg of L-phenylalanine by
Volume 92 Number 1
mouth and measuring the concentration of phenylalanine and tyrosine in the plasma over the next 8 hours. There was an abnormally high and sustained rise in the concentration of tyrosine 3 (Fig. 2). A fructose tolerance test at this time was normal. The infant was maintained on a protein-restricted diet, and treatment was begun with 100 mg of ascorbic acid per day. The plasma tyrosine had already become subnormal on 1 g m / k g / d a y dietary protein before ascorbic acid treatment was started and the urinary nitrosonaphthol test was only slightly positive. The infant lost weight gradually even though his caloric intake increased to almost 140 calories/kg/day; therefore the dietary protein was increased to 3 gm/kg/day. The urinary nitrosonapthol rose transiently to 3 §, but the plasma concentration of tyrosine remained normal. He began to gain weight. A repeat phenylalanine-tyrosine conversion test on day 37 was still markedly abnormal. The tyrosine concentration was 1.0 mg/dl at the start of the test, peaked at 5.9 mg/dl at 2 hours, and was 4.6 mg/dl at 8 hours. Assay of hepatic p-hydroxyphenylpyruvic acid hydroxylase showed 25% of normal activity (Table II). Simultaneous assay of tyrosine aminotransferase on the same specimen showed normal activity of this enzyme. DISCUSSION Elevated concentrations of tyrosine in plasma and increased urinary excretion of metabolites of tyrosine have been reported in the neonatal period as a result of hereditary tyrosinemia, 1 transient tyrosinemia of the premature?. :~ hereditary fructose intolerance,: galactosemia, 1 and neonatal hepatitis? Hereditary tyrosinemia is an autosomal recessive disorder characterized by progressive liver disease, elevated levels of tyrosine in plasma and usually an elevated plasma concentration of methionine when the patient is not receiving a protein-restricted diet, increased excretion of A-aminolevulinic acid, and the renal Fanconi syndrome. This clinical picture can also be seen in galactosemia and hereditary fructose intolerance.: Transient tyrosinemia usually resolves in the first months of life, s and it usually responds to treatment with ascorbic acid. In transient tyrosinemia, there is no evidence of hepatocellular injury or the renal Fanconi syndrome. Our patient had normal levels of plasma methionine at all times, and he did not excrete detectable levels of Aaminolevulinic acid. He did have evidence of continuing hepatocellular damage and a renal Fanconi syndrome. We were able to rule out galactosemia and fructose intolerance. The differential diagnosis includes transient tyro-
Tyrosinemia with C M V infection
111
sinemia of the premature and tyrosine aminotransferase deficiency, but the fact that neither is associated with hepatic dysfunction or renal Fanconi syndrome excludes these possibilities. Further, his phenylalanine-tyrosine tolerance test remained abnormal after 15 days of ascorbic acid therapy. His clinical picture remained basically consistent with that of hereditary tyrosinemia. The isolation of cytomegalovirus from the urine and the fact that the infant appeared to improve with time indicated that this unusual clinical picture may have been produced by the infection. The hepatic dysfunction displayed by this infant was consistent with congenital CMV infection. This agent was recovered from three separate urine specimens. Because of the known rapid fall in CMV titers after birth in some congenitally infected infants:: we are not able to state whether our patient was infected pre- or postnatally. Abnormalities of tyrosine metabolism due to CMV have apparently not previously been reported. The pathogenesis may be the same as that reported by Yu and co-workers ~ in three premature infants who had elevated plasma concentrations o f tyrosine not responsive to ascorbic acid, jaundice, rickets, and generalized aminoaciduria, in whom liver biopsies demonstrated a histologic picture consistent with neonatal hepatitis. Studies for congenital infections in these patients were negative, including cultures for CMV. The reduction in activity of hepatic p-hydroxyphenylpyruvate hydroxylase in our patient to 25% of normal is consistent with liver damage? In hereditary tyrosinemia as described in the French-Canadian isolate, levels of this enzyme are typically only 3 to 5% of control levels. 1 The histologic picture of cirrhosis and fibrosis in the liver in our patient is consistent with the sequelae of CMV disease. Cytomegalovirus inclusions are often not seen in this stage of the illness, '2 and his clinical picture, prior to the onset of pneumonia, was compatible with resolving CMV infection. These observations indicate that perinatal infection with cytomegalovirus can produce a clinical and biochemical picture that must be added to the differential diagnosis of hereditary tyrosinemia. We thank S. Kulovich for performing the amino acid analysis, Barbara McKeller and staff of the Clinical Virology Laboratory, University Hospital, San Diego, for performing the CMV cultures and titers, C. Burkey for performing the enzyme assays, and Dr. Kurt Benirschke and Dr. Marian Melish for helpful comments and criticism of the manuscript. REFERENCES
1. LaDu B, and Gjessing L: Tyrosinosis and tyrosir~emia, in Stanbury J, Wyngaarden J, and Fredrickson D: The meta-
112
2.
3. 4.
5.
6.
7.
Thoene et aL
bolic basis of inherited disease, ed 3, New York, 1972, McGraw-Hill Book Company, pp 296-307. Scriver C, Larochelle J, and Silverberg M: Hereditary tyrosinemia and tyrosyluria in a French Canadian geographic isolate, Am J Dis Child 113:41, 1967. Levine R, and Conn H: Tyrosine metabolism in patients with liver disease, J Clin Invest 46:2012, 1967. Yu J, Walker-Smith J, and Burnard E: Neonatal hepatitis in premature infants simulating hereditary tyrosinosis, Arch Dis Child 46:306, 1971. Buist N, Kennaway N, and Fellman J: Disorders of tyrosine metabolism, in Nyhan W, editor: Heritable disorders of amino acid metabolism, New York, 1974, John Wiley & Sons, Inc., p 165. Spackman D, Stein W, and Moore S: Automatic recording apparatus for use in the chromatography of amino acids, Anal Chem 30:1190, 1958. Sweetman L: Liquid partition chromatography and gas
The Journal of Pediatrics January 1978
8.
9.
10.
11.
12.
chromatography-mass spectrometry in identification of acid metabolites of amino acids, in Nyhan W, editor: Heritable disorders of amino acid metabolism, New York, 1974, John Wiley & Sons, Inc., pp 730-751. Fellman J, Fujita T, and Roth E: Assay, properties and tissue distribtution of p-hydroxyphenylpyruvate hydroxylase, Biochem Biophys Acta 284:90, 1972. Fellman J, Vanbellinghen P, and Koler R: Soluble and mitochondrial forms of tyrosinemia, Biochemistry 8:615, 1969. Rassin D, Gaull G, Raiha N, and Heinonen K: Milk protein quantity and quality in low birth weight infants IV Effects on tyrosine and phenylalanine in plasma and urine, J PEDIATR90:356, 1977. Melish M, and Hanshaw J: Congenital cytomegalovirus infection: Developmental progress of infants dectected by routine screening, Am J Dis Child 126:190, 1973. Melish M: Personal communication.
January 1978 The Journal o f P E D I A T R I C S
Tyrosinemia associated with perinatal infection with cytomegalovirus A premature infant presented with elevated concentrations of tyrosine in blood and urine, evidence of hepatocellular damage, demineralization of the bones, and a renal Fanconi syndrome. This is the clinical picture found in hereditary tyrosinemia. The infant also had a perinatal infection with cytomegalovirus. J . T h o e n e , M . D . , * L. S w e e t m a n , P h . D . , L a Jolla, Calif., T. S h a f a i , M . D . , P h . D . , Riverside, Calif., N . K e n n a w a y , D. Phil., J . F e l l m a n , P h . D . , Portland, Ore.,
and W . N y h a n , M . D . , P h . D . ,
L a Jolla, Calif.
TYROSINEMIA iS a syndrome which usually presents in the neonatal period with altered metabolism of tyrosine, evidence of hepatocellular damage, and a renal Fanconi syndrome. In most instances this disorder appears to be genetically determined? Evidence supporting an autosomal recessive transmission of tyrosinemia with this clinical picture has come from the study of a French-Canadian isolate. ~ However, abnormalities of tyrosine metabolism have been reported in adults with a variety of liver diseases 3 and in infants with neonatal hepatitis.' There is another form of inherited tyrosinemia in which tyrosine aminotransferase is deficient? It is the purpose of this communication to present the case report of a premature infant who presented at 3 months of age with the typical picture of tyrosinemia, including elevated plasma concentrations of tyrosine, abnormal conversion of phenylalanine to tyrosine, glycosuria, aminoaciduria, abnormal tests of liver function, and was shown to have infection with cytomegalovirus. Perinatal infection with From The Department of Pediatrics, University of California, San Diego, The Department of Pediatrics, Riverside General Hospital, University Medical Center, and The Division of Medical Genetics and Department of Biochemistry, University of Oregon, Health Sciences Center. Aided by United States Public Health Service Grants No. AM00321 and AM17906, from the National Institute of Arthritis, Metabolism, and Digestive Diseases, National Institutes of Health. *Reprint address: Department of Pediatrics, University of Michigan Medical Center, R6048 Kresge 1!, Ann Arbor, MI 48104.
Vol. 92, No. 1, pp. 108-112
C M V can apparently cause abnormalities in metabolism which closely mimic hereditary tyrosinemia. CASE REPORT
Patient R.D., a male infant who was born after approximately 28 weeks of gestation to unrelated Caucasian parents, was referred at 3 months of age because reducing substance was found in the urine. The birth weight was 795 gin, and the initial physical examination was unremarkable. He developed respiratory distress syndrome which required a ventilator for 3% weeks. Abbreviations used CMV: cytomegalovirus SGOT: serum glutamic oxalacetic transaminase SGPT: serum glutamic pyruvic transaminase PHPLA: p-hydroxyphenyllactic acid This was followed by intermettent apnea for 2 months. No hepatomegaly was noted. The serum concentration of bilirubin rose to 7.6 mg/dl, and he was treated with phototherapy. After an initial decline in the concentration of bilirubin the infant was found at 8 weeks of age to have a total bilirubin concentration of 8.1 mg/dl with 4.6 mg/dl direct. The liver was palpable 3 cm below the right costal margin. The hepatitis B surface antigen test was negative. The SGOT was 226 IU, the SGPT 58 IU, and the alkaline phosphatase 1,700 IU. At t2 weeks Of age he weighed 2,116 gm. The liver was still enlarged and liver function remained abnormal. The bilirubin had increased to 10.6/5.3 mg/dl. He had intermittent apnea. Alpha~-antitrypsin levels were in the normal range. At this time screening of urine for metabolic disease revealed 2 + reducing substance and 4 + nitrosonaphthol, indicating an elevation of urinary phenolic acids. The plasma concentration of tyrosine was 7.09 mg/dl (nl 0.5 to 1.8
Volume 92 Number 1
Tyrosinemia with C M V infection
10 9
2400
WEIGHT
2300
2200
i
i
i
i
i
i
f
i
i
,.,
3.0 DIETARY PROTEIN
2.0
( glKg/day ) 1.0
o 16o DIETARY CALORIES
140
callKg/doy 120
100'
t
4.0
5.0 PLASMA TYROSINE
2.0
mgldl 1.0
THERAPY
i
URINARY NITROSONAPHTHOL BILIRUBIN ALKALINE PHOSPHATASE
Vii.
+
+ + + +
+
-i- +
Z0/2.7
6.2/2.0
I
1780 O'
Ascorbic A c i d l O 0 m g / d 0 y I D 5000 u. per day + TR
5.8/I.5
' rO
' 15
+
4 . 9 / I . 5 5.1/I.5
1428 5
44-
187 2'0
2'5
' 50
3'5
4'0
HOSPITAL DAY
Fig. 1. Graphic summary o f the hospital course. mg/dl) and the concentration of methionine with 0.62 mg/dl (nl 0.13 to 0.61). He was subsequently transferred to University Hospital, San Diego. On admission, the infant was a small, malnourished Caucasian male with greenish skin. The sclerae were icteric. He weighed 2,280 gm. A smooth liver edge was palpable 3 cm below the right costal margin. Physical examination was otherwise unremarkable. Electrolyte analysis and complete blood count were within normal limitsl The serum concentration of bilirubin was 7.0/2.7 mg/dl. The SGOT was 166 IU; the SGPT was 48 IU; the alkaline phosphatase 1,780 IU; and the concentration of NH3 79. The serum concentration of Ca*+ was 8.9, PO4 3.2, blood Urea nitrogen 3, and glucose 36 mg/dl. Titers for rubella and herpes were each < 1:8 on two occasions. The titer to glycine extracted
CMV antigen was 1:64. A quantitative VDRL and adsorbed fluorescent treponemal antibody were negative. The IgM at 4 months of age was 46 mg/dl. Roentgenograms of the long bones demonstrated severe demineralization and a pathologic fracture of the left distal ulna. Treatment was begun with vitamin D in a dose of 5;000 U per day, and evaluation of the abnormality in tyrosine metabolism was begun. Three separate urine cultures were positive for cytomegalovirus. By this time the serum concentration o f bilirubin had fallen to 5.1/1.5 mg/dl, the SGOT was 106 IU, and the alkaline phosphatase was 187 IU. He was discharged to the care o f his parents, feeding well, and gaining weight. At 7 months the patient developed an acute bronchopneumonia, rapidly became comatose, and died. An autopsy showed
1 10
Thoene et al.
The Journal of Pediatrics January 1978 Table I. Concentrations of amino acids and organic acids in the blood and urine
I0.0
9.0
Plasma (mg/dl)
Hospital day Tyrosine Methionine
8.0
1 2 5 8 l0 13 14 21
7.0
6.0
\
5,0
E
1.09
Urine tyrosine (rag~rag ereatinine)
0.38 0.038
3.94
0.37
0.32
0.22
0.315
Urine PHPLA (l~mol/mg creatinine) 2.72 2,90 6,70 13,60 14.80 3.80 2.00
4.0 Table II. Activity of hepatic p-hydroxyphenylpyruvate hydroxyiase and tyrosine aminotransferase in the patient and normal controls
7.0 2.0
p-Hydroxyphenylpyruvate hydroxylase
1.0 9
i
0
2
i
46 HOURS
i
8
extensive hepatic cirrhosis and fibrosis. There were multinucleated giant cells in liver, kidney, and lung, consistent with a systemic viremia. Cytomegalovirus inclusion particles were not demonstrated. METHODS
pmole/mg protein/hr
l'O
Fig. 2. Phenylalanine tolerance test performed by the oral administration of 100 mg/kg of L-phenylalanine on hospital day 23 (e plasma phenylalanine, oplasma tyrosine).
AND RESULTS
Samples of plasma and urine for amino acid analysis were kept on ice until deproteinized with 4% sulfosalicylic acid, and analyzed on a Beckman 120 amino acid analyzer# P-Hydroxyphenyllactic acid was quantitated by automatic spectrophotometric titration of urinary acids eluted from a liquid partitition chromatographic column.' Identification of urinary organic acids was done by gas chromatography-mass spectrometry of the trimethylsilyl derivatives.' Assay of hepatic p-hydroxyphenylpyruvic acid hydroxylase and tyrosine aminotransferase were performed as previously described. 8, 9 The infant was given a diet which supplied 105 calories/kg/day and 1 g m / k g / d a y of protein, consisting of Enfamil, Polycose, and medium-chain triglycerides, After the institution of this diet, the plasma concentration of
Tyrosine aminotransferase
Patient R.D. Control 1 Control 2
0.097 0.40 0.48
0.46 0.57 0.60
tyrosine was found to be 1.09 mg/dl and the urinary nitrosonaphthol was 1+. After nine days of this diet, he was given Enfamil ad lib and injested approximately 3 gm/kg/day of protein and 105 calories/kg/day. The plasma concentration of tyrosine rose rapidly to 3.94 rag/d1, and the urinary nitrosonapthol rose to 3 ~ (Fig 1). Quantitation of the urinary organic acids showed an elevation of PHPLA from 2.72 ~tmol/mg creatinine on admission to 14.8/~mol/mg creatinine on day 10 (Table I), when he was receiving 3 gm/kg of dietary protein. There was a generalized aminoaciduria. The urinary excretion of tyrosine was 0.315 mg/mg creatinine on day 10. Plasma concentrations of amino acids other than tyrosine were normal. The concentration of methionine was not elevated. A-Aminolevulinic acid was not found in the urine. A diet restricted in protein to 1.0 g m / k g / d a y was reinstituted (Fig. 1) and the plasma concentration of tyrosine again fell rapidly to normal. A phenylalaninetyrosine conversion test was performed on day 23 by administering a load of 100 mg/kg of L-phenylalanine by
Volume 92 Number 1
mouth and measuring the concentration of phenylalanine and tyrosine in the plasma over the next 8 hours. There was an abnormally high and sustained rise in the concentration of tyrosine 3 (Fig. 2). A fructose tolerance test at this time was normal. The infant was maintained on a protein-restricted diet, and treatment was begun with 100 mg of ascorbic acid per day. The plasma tyrosine had already become subnormal on 1 g m / k g / d a y dietary protein before ascorbic acid treatment was started and the urinary nitrosonaphthol test was only slightly positive. The infant lost weight gradually even though his caloric intake increased to almost 140 calories/kg/day; therefore the dietary protein was increased to 3 gm/kg/day. The urinary nitrosonapthol rose transiently to 3 §, but the plasma concentration of tyrosine remained normal. He began to gain weight. A repeat phenylalanine-tyrosine conversion test on day 37 was still markedly abnormal. The tyrosine concentration was 1.0 mg/dl at the start of the test, peaked at 5.9 mg/dl at 2 hours, and was 4.6 mg/dl at 8 hours. Assay of hepatic p-hydroxyphenylpyruvic acid hydroxylase showed 25% of normal activity (Table II). Simultaneous assay of tyrosine aminotransferase on the same specimen showed normal activity of this enzyme. DISCUSSION Elevated concentrations of tyrosine in plasma and increased urinary excretion of metabolites of tyrosine have been reported in the neonatal period as a result of hereditary tyrosinemia, 1 transient tyrosinemia of the premature?. :~ hereditary fructose intolerance,: galactosemia, 1 and neonatal hepatitis? Hereditary tyrosinemia is an autosomal recessive disorder characterized by progressive liver disease, elevated levels of tyrosine in plasma and usually an elevated plasma concentration of methionine when the patient is not receiving a protein-restricted diet, increased excretion of A-aminolevulinic acid, and the renal Fanconi syndrome. This clinical picture can also be seen in galactosemia and hereditary fructose intolerance.: Transient tyrosinemia usually resolves in the first months of life, s and it usually responds to treatment with ascorbic acid. In transient tyrosinemia, there is no evidence of hepatocellular injury or the renal Fanconi syndrome. Our patient had normal levels of plasma methionine at all times, and he did not excrete detectable levels of Aaminolevulinic acid. He did have evidence of continuing hepatocellular damage and a renal Fanconi syndrome. We were able to rule out galactosemia and fructose intolerance. The differential diagnosis includes transient tyro-
Tyrosinemia with C M V infection
111
sinemia of the premature and tyrosine aminotransferase deficiency, but the fact that neither is associated with hepatic dysfunction or renal Fanconi syndrome excludes these possibilities. Further, his phenylalanine-tyrosine tolerance test remained abnormal after 15 days of ascorbic acid therapy. His clinical picture remained basically consistent with that of hereditary tyrosinemia. The isolation of cytomegalovirus from the urine and the fact that the infant appeared to improve with time indicated that this unusual clinical picture may have been produced by the infection. The hepatic dysfunction displayed by this infant was consistent with congenital CMV infection. This agent was recovered from three separate urine specimens. Because of the known rapid fall in CMV titers after birth in some congenitally infected infants:: we are not able to state whether our patient was infected pre- or postnatally. Abnormalities of tyrosine metabolism due to CMV have apparently not previously been reported. The pathogenesis may be the same as that reported by Yu and co-workers ~ in three premature infants who had elevated plasma concentrations o f tyrosine not responsive to ascorbic acid, jaundice, rickets, and generalized aminoaciduria, in whom liver biopsies demonstrated a histologic picture consistent with neonatal hepatitis. Studies for congenital infections in these patients were negative, including cultures for CMV. The reduction in activity of hepatic p-hydroxyphenylpyruvate hydroxylase in our patient to 25% of normal is consistent with liver damage? In hereditary tyrosinemia as described in the French-Canadian isolate, levels of this enzyme are typically only 3 to 5% of control levels. 1 The histologic picture of cirrhosis and fibrosis in the liver in our patient is consistent with the sequelae of CMV disease. Cytomegalovirus inclusions are often not seen in this stage of the illness, '2 and his clinical picture, prior to the onset of pneumonia, was compatible with resolving CMV infection. These observations indicate that perinatal infection with cytomegalovirus can produce a clinical and biochemical picture that must be added to the differential diagnosis of hereditary tyrosinemia. We thank S. Kulovich for performing the amino acid analysis, Barbara McKeller and staff of the Clinical Virology Laboratory, University Hospital, San Diego, for performing the CMV cultures and titers, C. Burkey for performing the enzyme assays, and Dr. Kurt Benirschke and Dr. Marian Melish for helpful comments and criticism of the manuscript. REFERENCES
1. LaDu B, and Gjessing L: Tyrosinosis and tyrosir~emia, in Stanbury J, Wyngaarden J, and Fredrickson D: The meta-
112
2.
3. 4.
5.
6.
7.
Thoene et aL
bolic basis of inherited disease, ed 3, New York, 1972, McGraw-Hill Book Company, pp 296-307. Scriver C, Larochelle J, and Silverberg M: Hereditary tyrosinemia and tyrosyluria in a French Canadian geographic isolate, Am J Dis Child 113:41, 1967. Levine R, and Conn H: Tyrosine metabolism in patients with liver disease, J Clin Invest 46:2012, 1967. Yu J, Walker-Smith J, and Burnard E: Neonatal hepatitis in premature infants simulating hereditary tyrosinosis, Arch Dis Child 46:306, 1971. Buist N, Kennaway N, and Fellman J: Disorders of tyrosine metabolism, in Nyhan W, editor: Heritable disorders of amino acid metabolism, New York, 1974, John Wiley & Sons, Inc., p 165. Spackman D, Stein W, and Moore S: Automatic recording apparatus for use in the chromatography of amino acids, Anal Chem 30:1190, 1958. Sweetman L: Liquid partition chromatography and gas
The Journal of Pediatrics January 1978
8.
9.
10.
11.
12.
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