ON THE RENAL TUBULAR DAMAGE IN HEREDITARY TYROSINEMIA AND ON THE FORMATION OF SUCCINYLACETOACETATE AND SUCCINYLACETONE1

ABSTRACT. Fällström, S.-P., Lindblad, B. and Steen, G. (Department of Paediatrics, East Hospital, University of Gothenburg, Gothenburg, Department of Paediatrics, Molndal's Hospital, Molndal, Department of Clinical Chemistry, University of Gothenburg, Gothenburg, Sweden). On the renal tubular damage in hereditary tyrosinemia and on the formation of succinylacetoacetate and succinylacetone. Acta Paediatr Scand, 70:315, 1981.–Phenylalanine and homogentisate increase the concentration of succinylacetoacetate and succinylacetone both in serum and urine in patients with hereditary tyrosinemia and therefore increase the excretion of 5-aminolevulinate. Both phenylalanine and homogentisate cause a tubular proteinuria which is in agreement with our hypothesis that their metabolites maleylacetoace-tate and fumarylacetoacetate are the toxic compounds in hereditary tyrosinemia. The patient with the highest excretion of succinylacetoacetate and succinylacetone has the slightest tubular proteinuria whereas the one with the lowest excretion of these compounds has the more pronounced tubular proteinuria. It is suggested that this is caused by a difference in the ability to reduce the presumed toxic compounds fumarylacetoacetate and maleylacetoacetate, i.e. the precursors of succinylacetoacetate.     

Rapid improvement in the renal tubular dysfunction associated with tyrosinemia following hepatic replacement.

The postoperative management of patients with hereditary tyrosinemia type I (McKusick 27670) following liver transplantation is often complicated by the renal tubular dysfunction associated with this disease. To characterize better the temporal course of the improvement in renal excretory activity following hepatic replacement, renal tubular function and metabolite excretion were studied in a 4-year-old girl with hereditary tyrosinemia during the immediate post-transplantation course. Tubular reabsorption of bicarbonate and phosphate were normal 5 days following transplantation, in contrast to glucosuria, hyperaminoaciduria, and tyrosyluria, which persisted for approximately 3 weeks. After hepatic replacement, serum amino acid concentrations returned to normal and succinylacetone was no longer detected in the urine. This is the third tyrosinemia patient reported to achieve complete resolution of urinary abnormalities following transplantation, and the only patient in whom renal tubular function was formally assessed within the first postoperative week.     

Succinylacetone and delta-aminolevulinic acid dehydratase in hereditary tyrosinemia: immunochemical study of the enzyme

Immunochemical determinations of delta-aminolevulinic acid (ALA) dehydratase were performed in erythrocytes and in liver of a patient with hereditary tyrosinemia who underwent liver transplantation for correction of this metabolic disorder. Both erythrocytic and hepatic ALA dehydratase activities were extremely low before liver transplantation, but they appeared normal after transplantation. According to results of immunochemical quantification of ALA dehydratase, the level of the enzyme protein in erythrocytes was not different before, during, and after liver transplantation. Immunoquantifiable enzyme concentrations were not substantially different in the patient's own liver as compared with the transplanted liver. These findings indicate that although succinylacetone, an abnormal metabolite produced in tyrosinemia, is a potent inhibitor of the activity of ALA dehydratase, it has a far less effect on the synthesis of the enzyme protein.     

HEREDITARY TYROSINEMIA

The clinical and biochemical findings in the case of an infant with hereditary tyrosinemia followed from birth have been reported. The child received a low protein diet from birth and a formula diet restricted in phenylalanine and tyrosine when the diagnosis was established at 54 days of age. There was a steady progress of the disease and the baby died from liver failure complicated with septicemia when he was 5½ months old. The clinical course and the biochemical findings as well as the morphological changes were typical of the acute type of the disease. A 6½ year old brother suffers from the same disease of the chronic type and the two types of hereditary tyrosinemia therefore seem to belong to the same genotype. The biochemical data from the patient with hereditary tyrosinemia have been compared with those in a healthy looking baby with longstanding and pronounced transient tyrosinemia of early infancy. The patterns of amino acids in blood and of phenolic acids in urine were similar in the two patients and it is concluded that an early laboratory differential diagnosis between hereditary tyrosinemia and transient tyrosinemia may only be made by observing the biochemical response to a diet restricted in tyrosine and phenylalanine in combination with the results of phenylalanine tolerance tests. The clinical features of hereditary tyrosinemia can apparently not be attributed to a high serum-tyrosine concentration or to the overproduction of phenolic acids; the lack of effect of early restriction in the intake of phenylalanine and tyrosine indicates a more complex pathogenesis of hereditary tyrosinemia than a primary deficiency of p-hydroxyphenylpyruvate hydroxylase.     

Early liver transplantation is indicated for tyrosinemia type I

Liver transplantation is now accepted as the treatment of choice for tyrosinemia type I (hereditary tyrosinemia). In an effort to determine whether any factors in these patients would aid in predicting optimal timing of the transplant procedure, we evaluated several clinical, biochemical, and radiographic parameters in five successive patients undergoing liver transplant for tyrosinemia type I at the University of Minnesota. All five patients evidenced prolonged periods of clinical and metabolic stability with dietary therapy and four of five remained stable at the time of evaluation for transplantation. Nevertheless, all five suffered significant and unexpected complications of tyrosinemia prior to the time of liver transplant. Four developed renal stones, two were in liver failure, and one developed a neurologic crisis that left him completely paralyzed. Hepatocellular carcinoma was found in one of the five at transplant. We could identify no clinical, biochemical, or radiographic study that was predictive of the likelihood of significant complications of the disorder. Survival from the transplant procedure itself was 100%. The inability to predict or prevent significant complications of tyrosinemia and the favorable outcome from transplantation lead us to recommend liver transplant for all patients with tyrosinemia type I by 12 months of age.     

Hereditary tyrosinemia of chronic course without rickets and renal tubular dysfunction

Three patients with hereditary tyrosinemia type 1, two brothers and one girl, studied at the age of 5, 12 and 15 years, respectively, had neither generalized hyperaminoaciduria, glucosuria nor clinical symptoms of rickets. Untreated the elder brother had only slightly elevated plasma tyrosine level (141 mumol/l, normal less than 80), and low excretion of p-hydroxyphenyllactate. He presented with pronounced thrombocytopenia (3 X 10(9)/l). At 13 years of age he contracted hepatocellular carcinoma. The younger brother presented with serum tyrosine of 318 mumol/l and thrombocyte count 48 X 10(9)/l. Succinylacetone in urine was elevated in both, 30 and 79 mumol/mmol creatinine, respectively. The female patient was investigated for hepatomegaly in infancy, atypical tyrosinemia being considered, but afterwards developed normally without diet or any other treatment until she contracted hepatoma at the age of 15 years. Her plasma tyrosine level was 600-700 mumol/l, and she excreted large amounts of p-hydroxyphenyllactate. Succinylacetone in urine was low but elevated (8 mumol/mmol creatinine). The fumarylacetoacetase activity in fibroblasts from the brothers and in lymphocytes from the girl was less than 5% and 10% of control levels, respectively. In conclusion, the chronic form of hereditary tyrosinemia may occur without evidence of renal tubular dysfunction.     

Hereditary Tyrosinemia of Chronic Course without Rickets and Renal Tubular Dysfunction

ABSTRACT. Three patients with hereditary tyrosinemia type 1, two brothers and one girl, studied at the age of 5, 12 and 15 years, respectively, had neither generalized hyperaminoaciduria, glucosuria nor clinical symptoms of rickets. Untreated the elder brother had only slightly elevated plasma tyrosine level (141 μmol/l, normal <80), and low excretion of p-hydroxyphenyllactate. He presented with pronounced thrombocytopenia (3 × 10⁹/1). At 13 years of age he contracted hepatocellular carcinoma. The younger brother presented with serum tyrosine of 318 μol/l and thrombocyte count 48 × 10⁹/1. Succinylacetone in urine was elevated in both, 30 and 79 μmol/mmol creatinine, respectively. The female patient was investigated for hepatomegaly in infancy, atypical tyrosinemia being considered, but afterwards developed normally without diet or any other treatment until she contracted hepatoma at the age of 15 years. Her plasma tyrosine level was 600-700 μmol/1, and she excreted large amounts of p-hydroxyphenyllactate. Succinylacetone in urine was low but elevated (8 μmol/mmol creatinine). The fumarylacetoacetase activity in fibroblasts from the brothers and in lymphocytes from the girl was less than 5% and 10% of control levels, respectively. In conclusion, the chronic form of hereditary tyrosinemia may occur without evidence of renal tubular dysfunction.     

活体肝移植治疗Ⅰ型酪氨酸血症的疗效

目的 探讨活体肝移植治疗Ⅰ型酪氨酸血症(HT Ⅰ)的手术疗效和预后.方法 2013年7月至2015年5月,4例确诊为HT Ⅰ的患儿(3男1女)在我中心接受了活体肝移植手术,手术指征均为肝硬化失代偿及AFP过高.患儿术前Child分级:B级3例,C级1例.患儿中位手术年龄4.4岁(1.9～5.9岁),供体均为患儿父母.患儿术后中位随访时间17个月(9～24个月).结果 4例活体肝移植手术供、受体均手术顺利,术后恢复良好.患儿术后酪氨酸代谢恢复正常,异常代谢产物琥珀酰丙酮(SA)、琥珀酰乙酰乙酸(SAA)、延胡索酰乙酰乙酸(FAA)和马来酰乙酰乙酸(MAA)的血清水平下降到测不出水平,肝功能和AFP在随访期间都维持正常.术后电解质水平恢复正常,肾功能维持稳定.所有患儿术后均表现出追长趋势.并发症方面,1例患儿出现EBV病毒感染和急性排斥反应,1例患儿术后存在乳糜漏和反复腹水,1例患儿出院后6个月感染手足口病病毒,均得以治愈.结论 活体肝移植是治疗HTⅠ的有效方式,术后患儿的代谢异常、肝肾功能和AFP水平均恢复正常,其术后生存率令人满意,但长期随访应注意肾功能的检测.     

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.     

Biochemical studies of a patient with hereditary hepatorenal tyrosinemia: evidence of glutathione deficiency

Metabolic and enzymatic studies in a patient with hereditary tyrosinemia demonstrated for the first time a deficiency of erythrocyte and hepatic glutathione. Markedly decreased hepatic fumarylacetoacetate hydrolase activity was demonstrated in this patient. The activities of hepatic enzymes not involved in tyrosine metabolism were also determined. Assay of mixed function oxidase activity demonstrated low levels of aryl hydrocarbon hydroxylase and 7-ethoxycoumarin deethylase, suggesting decreased hepatic detoxification capacity. 5-Aminolevulinic acid dehydratase activity was undetectable. Succinylacetone (4,6-dioxoheptanoic acid), an abnormal metabolic product secondary to fumarylacetoacetate hydrolase deficiency was found in serum and urine. Succinylacetone was demonstrated to inhibit 5-aminolevulinic acid dehydratase in vitro, as did the urine, plasma, and red cell lysates of the patient.     

Metabolic studies of a family with massive formiminoglutamic aciduria.

We have described two siblings who excrete massive amounts (up to 3.89 mmol/24 hr) of N-formiminoglutamic acid (FIGLU) in their urine. This unusual compound was isolated from urine, purified, and firmly identified as FIGLU by combined gas chromatography-mass spectrometry. The patients presumably have a deficiency in activity of the hepatic enzyme, glutamate formiminotransferase, which carries out the fourth sequential step in the main pathway of histidine degradation. Unlike children reported previously with this disorder, our patients had normal serum folate levels, had no hematologic abnormalities, and were not mentally retarded. Very small amounts of FIGLU were present in the plasma of one of the patients, but FIGLU was not detectable in the cerebrospinal fluid of either patient. Administration of pharmacologic doses of folic or folinic acid produced a decrease in excretion of FIGLU in urine. Histidine loading caused a small and comparable urinary excretion of FIGLU in the children's parents and in control adult subjects.     

Episodic hypoglycemia with psi-hydroxy fatty acid excretion

We present case histories of two young children with episodes of hypoglycemia, elevation of SGOT, low insulin levels, increased urinary excretion of psi-hydroxy fatty acids (5-hydroxyhexanoic, 7-hydroxyoctanoic and 9-hydroxydecanoic), traces of the corresponding psi-ketoacids and elevations of urinary adipic, suberic, and sebacic acids. The ratio of psi-hydroxy fatty acids to 3-hydroxybutyric in the urine of these patients is higher than in patients of similar ages with similar illnesses. These acids persisted while the patients were well. Increased urinary psi-hydroxy fatty acids could be reproduced by a load of medium chain triglycerides without precipitating other clinical symptoms. Three children with hypoglycemia were found not to excrete measurable amounts of these unusual acids while ill. A medium chain triglyceride load in one of these children after recovery failed to elicit psi-hydroxy acid excretion. Small amounts of urinary 5-hydroxyhexanoic acid only were found in two patients with acute Reye's syndrome and in three of five severely ill children with starvation ketonuria. In this last group, no urinary psi-hydroxyacids could be detected after recovery. Normal children do not excrete measurable amounts (less than 1 mg/g creatinine) of these psi-hydroxyacids.     

Galactose metabolism by the mouse with galactose-1-phosphate uridyltransferase deficiency

The ability of mice deficient in galactose-1-phosphate uridyltransferase (GALT) to metabolize galactose was determined in animals weaned to a mouse chow diet for a 4-wk period. When given [14C]galactose intraperitoneally, these animals slowly oxidized the sugar, excreting only 5.5% of the dose as 14CO2 in 4 h, whereas normal animals excreted 39.9%. These results mimic those seen in human galactosemic patients given isotopic galactose. When given 10 micromol of [1-13C]galactose, normal animals excrete small amounts of labeled galactose and galactonate but no galactitol in urine whereas GALT-deficient mice excrete significant amounts of all of these as labeled compounds in urine. When challenged with galactose, only about 20% of the dose is excreted in urine, and even on the chow diet, significant amounts of galactose, galactonate, and galactitol are excreted in urine. These compounds are also found to be present in liver, kidney, and brain, except that galactonate is not found in brain. Galactose-1-phosphate accumulates in red blood cells to levels found in humans exposed to large amounts of galactose, and galactose-1-phosphate is found in increased amounts in liver, kidney, and brain of GALT-deficient animals. There was no difference in the hepatic concentration of uridine diphosphate galactose and uridine diphosphate glucose between normal and GALT-deficient mice. The explanation for the presence of galactose and its conversion products in tissues and urine of affected mice appears to be related to the presence of approximately 1.75% of galactose-containing carbohydrates in the chow, which becomes bioavailable to mice. Despite the presence of galactose and its metabolites in tissues and urine and impaired ability to oxidize the sugar, the GALT-deficient animals are indistinguishable from normal animals and do not exhibit the phenotype of humans with GALT-deficiency galactosemia.     

血尿琥珀酰丙酮检测在酪氨酸血症-Ⅰ型诊断中的应用

目的 探讨血、尿琥珀酰丙酮检测在酪氨酸血症-Ⅰ型诊断中的价值.方法 对临床疑似酪氨酸血症、血串联质谱检测酪氨酸水平增高的190例患儿,进行血串联质谱琥珀酰丙酮检测、尿气相色谱-质谱琥珀酰丙酮及有机酸检测.确诊条件为临床表现、血酪氨酸增高及血或尿琥珀酰丙酮增高.结果 确诊酪氨酸血症-Ⅰ型患儿11例,男9例,女2例,年龄2个月至6岁.患儿血琥珀酰丙酮显著升高( 14.2±7.8) μmol/L(参考值1～5μmol/L).其中7例患儿进行了尿气相色谱-质谱琥珀酰丙酮检测,4例阳性,3例阴性.血酪氨酸水平为(327.3±125.8) μmol/L(参考值为20 ～ 100μmol/L).临床表现均有肝肿大.结论 血或尿琥珀酰丙酮升高是诊断酪氨酸血症-Ⅰ型的最重要依据.串联质谱检测血琥珀酰丙酮较气相色谱-质谱检测尿琥珀酰丙酮对诊断酪氨酸血症-Ⅰ型更可靠,气相色谱-质谱尿琥珀酰丙酮检测可能导致假阴性.     

A PATIENT WITH HEREDITARY GALACTOKINASE DEFICIENCY

A case of hereditary galactokinase deficiency is reported, occurring in a newborn boy and detected through routine screening of newborns for increased blood concentration of galactose. Symptoms were equivocal and consisted only of mild feeding difficulties and a slightly insufficient weight gain. The only abnormality found on clinical examination was lens opacities which were obvious when the boy was 5 weeks old. The biochemical abnormalities found were: excretion of large amounts of galactose and ga-lactitol in the urine, galactosemia, and essentially no galactokinase activity in the red blood cells. On a galactose-free diet, introduced when the boy was 3½ weeks old, he grew and developed normally, his cataracts had improved considerably after 4 months. The boy's both parents, one brother and possibly one sister were considered carriers of the autosomal recessive gene, as the enzyme activity found in their red blood cells was roughly half of the normal value. The clinical findings in patients with the various enzyme defects leading to galactosemia are described and related to the biochemical abnormalities caused by the defects. Possible screening methods are discussed.     

Metabolic studies of transient tyrosinemia in premature infants.

The recently developed technique of gas chromatography-mass spectrometry supported by computer has considerably improved the analysis of physiologic fluids. This study attempted to demonstrate the value of this system in the investigation of metabolite patterns in urine in two metabolic problems of prematurity, transient tyrosinemia and late metabolic acidosis. Serial 24-hr urine specimens were analyzed in 9 infants. Transient tyrosinemia, characterized by 5-10-fold increases over basal excretion of tyrosine, p-hydroxyphenyllactate, and p-hydroxyphenylpyruvate in urine, was noted in five of the infants. Several infants had fluctuating levels of tyrosine metabolites in urine although dietary protein intake remained constant at 3-4 g/kg/24 hr and ascorbic acid at 50 mg/24 hr. Late metabolic acidosis was seen in four infants, but bore no relation to transient tyrosinemia. The ratio of net acid to urea excretion in urine increased with increasing base deficit, implying a nonprotein origin of the metabolic acid. No unique metabolic patterns were characteristic of late metabolic acidosis.     

Prenatal diagnosis of hereditary tyrosinemia by determination of fumarylacetoacetase in cultured amniotic fluid cells

Fumarylacetoacetase was assayed in cultured amniotic fluid cells from four pregnancies at risk for hereditary tyrosinemia and in 11 controls. The enzyme activity was normal in three of the pregnancies at risk for tyrosinemia and healthy children were born. In the fourth case the enzyme activity was deficient, indicating an affected fetus. As the pregnancy was very advanced it was continued, and the child has tyrosinemia. One parent in one of the four families is a compound heterozygote for the tyrosinemia gene and the recently reported "pseudodeficiency" gene for fumarylacetoacetase. This has important consequences for prenatal diagnosis in this family.     

Tyrosinemia type I—Diagnostic issues and prenatal diagnosis

A fifteen-month-old boy, born to consanguineously married couple, presented with asymptomatic hepatomegaly. Investigations revealed midly deranged liver functions, necroinflammatory changes and cirrhosis on liver biopsy, a markedly raised alpha feto protein and tyrosine levels in plasma and a generalized aminoaciduria. His diagnosis of hereditary tyrosinemia was established on findings of raised serum and urine succinylacetone, and a deficient activity of fumaryl acetoacetate hydroxylase enzyme. Prenatal diagnosis of hereditary tyrosinemia was performed in a subsequent pregnancy in this family from India.     

ENZYMATIC STUDIES IN A CASE OF HEREDITARY TYROSINEMIA WITH HEPATOMA

The activity of δ-aminolevulinic acid synthetase has been measured in liver and hepatoma tissue from a case of hereditary tyrosinemia with an increased excretion of δ-aminolevulinic acid in the urine. The enzyme activity in the hepatoma tissue was seven times higher than in the surrounding liver, where the activity was not increased above the reported normal range. The activity of p-hydroxyphe-nylpyruvate hydroxylase (EC 1.14.2.2.) was about 25 % of the normal in the liver tissue but not measurable in the hepatoma. Tyrosine aminotransferase (EC 2.6.1.5.) activity was normal in the liver tissue but was not detectable in the hepatoma, whereas the activity of phenylpy-ruvate keto-enol isomerase (EC 5.3.2.1.) was the same in liver and hepatoma tissue.     

D(+)-glyceric aciduria: etiology and clinical consequences

A family comprising mother, father, and five children is described. Four of the children were found to excrete massive amounts of D(+)-glyceric acid in their urine. This was verified by gas chromatography-mass spectrometry and the configuration determined by capillary gas chromatography of O-acetylated menthyl esters. The excretion ranged from 10.8 to 19.9 mmol/24 h. The remaining child and the parents showed no evidence of this unusual metabolite. The virtual absence of clinical manifestations in this family was particularly interesting. Only two of the children showed any clinical abnormality and this was limited to mild microcephaly and speech delay; the other two children found to excrete large amounts of D(+)-glycerate were healthy and developmentally normal at 7 y and 9 y of age. There was a marked increase in the excretion rate of D(+)-glycerate in response to both oral fructose and serine loading. These results are consistent with a deficiency of D(+)-glycerate kinase and indicate the potentially benign nature of this disorder.