[Juvenile form of tyrosinemia type I]

A 1-3/12-year-old Turkish boy born of consanguineous parents was hospitalized in poor general condition with disorientation, hepatosplenomegaly, and rickets. Laboratory tests showed pronounced symptoms of hepatic dysfunction, rickets, and Fanconi's syndrome with acidosis. The diagnosis juvenile type I tyrosinemia was based on the anamnesis, hepatorenal symptoms, and elevated tyrosine and methionine blood levels as well as the pathognomic findings of heavy succinylacetonuria and absent fumarylacetoacetase activity in the fibroblasts. Etiology, pathobiochemistry, clinical symptoms, differential diagnosis, and therapy of this rare autosomal-recessive inherited metabolic disease were discussed.

Dietary treatment of hyperlysinaemia

We describe the lysine restricted, dietary management of three out of four siblings who were identified as having hyperlysinaemia. The diets, started in the neonatal period, were maintained for varying periods with unpredictable success. The propositus, who was not treated, was diagnosed at the age of 5 years, by which time he was already severely handicapped, presumably because of his metabolic disorder. Tentative recommendations are put forward for the management of this seemingly rare disorder. Mild chronic ammonia toxicity may be a factor in the pathogenesis of this condition.

Lactulose in trimethylaminuria, the fish-odour syndrome

We have measured the urinary excretion of trimethylamine in two sisters with trimethylaminuria (the fish-odour syndrome). On a restricted diet the patients still excreted increased quantities of trimethylamine, and this did not alter following a fourteen-day course of lactulose. Dietary provocation produced a rise in urinary trimethylamine which was abolished by fourteen days' pretreatment with lactulose. The case histories illustrate the tendency for delay in reaching this diagnosis and the psychological damage caused by the condition.

Ornithine transcarbamylase deficiency in a male: strict correlation between metabolic control and plasma arginine concentration

In a male with a partial defect of ornithine transcarbamylase (OTC) we observed that maintenance of arginine supply was crucial for adequate metabolic control in conjunction with a low protein diet. The arginine supplement had to be given such that the concentrations of arginine and ornithine in plasma were above 50 mumol/l. It appears that arginine is needed not only as an essential amino acid for protein synthesis but also as a precursor of ornithine. In this patient the substitution thus aimed at increasing the intramitochondrial ornithine in order to reach a critical substrate concentration for the kinetically abnormal OTC.

[Protein intolerance with lysinuria. Value of orotic aciduria in adjusting treatment with citrulline]

A new case of lysinuric protein intolerance is described in a 14 year-old Maghrebian child who presented with growth failure, vertebral osteoporosis, aversion to proteins and digital hippocratism, rarely described in this disease. Orotic aciduria was studied after a protein load with and without citrulline supplement and during the course of a 11 month-treatment. There was a clear relationship between orotic aciduria, protein intake and citrulline supplementation. Orotic aciduria appears to be very useful to adjust the treatment.

Isovaleric acidemia: medical and neurodevelopmental effects of long-term therapy

Nine patients with isovaleric acidemia were treated with a low-protein diet and supplemental glycine for up to 10 years. Carnitine was added to the therapy in four patients. Overall, the treatment was well tolerated, resulting in no significant side effects other than persistent hyperglycinemia. Normal growth was observed in all patients. Of four patients with the chronic phenotype, three, whose treatment was delayed beyond the first year of life, are mentally retarded. Two of five patients with the acute phenotype are retarded. The outcome in these two was complicated in one by neonatal intraventricular hemorrhage and in the other by therapeutic noncompliance. In our patients, only those who were treated successfully from early infancy and had no complications did not develop mental retardation. After initiation of therapy, there was a significant decrease in ketoacidotic attacks requiring hospitalization. Glycine is indicated for the treatment of acute ketoacidosis in these patients; none of the catastrophically ill newborn who received glycine died. The aim of treatment is to reduce the isovaleric acid burden to a minimum. Therapy consisting of leucine restriction with supplemental glycine and carniline should be started as soon as possible after birth.

[Treatment of citrullinemia. Apropos of a case followed from birth. Importance of alpha-ketonic acids]

From day 1 to day 3, the protein intake of this neonate was restricted to 1 g/kg/d. It included a) essential amino acids (i.e. histidine, lysine, threonine, tryptophan), b) arginine (1,000 mg/d), c) alphaketoisovaleric 500 mg/d, alpha-ketoisocaproic (500 mg/d), alphaketobetamethylvaleric (500 mg/d), alphaketogammamethylthiobutyric (200 mg/d), betaphenylpyruvic (400 mg/d) acids. 250 mg/kg/d of sodium benzoate were given. Caloric and water intakes were 120 cal/kg/d and 120 ml/kg/d respectively. Afterwards, this procedure was modified according to clinical and biological data including serum ammonia and amino acid levels. Alpha-ketonic acid absorption and metabolism were studied on day 29. Both were fast. The detection of alloisoleucine, which is not metabolized was the consequence of the use of alphaketobetamethylvaleric acid. Until the age of 21 months, clinical and metabolic status was satisfactory. At this time, repeated seizures without metabolic failure were accompanied by psychomotor damages.

Carnitine deficiency in lysinuric protein intolerance: lysine-sparing effect of carnitine

Plasma carnitine deficiency (41% of normal control) was found in a 9 year-old boy with lysinuric protein intolerance. Following oral carnitine administration, the plasma level of lysine as well as carnitine has significantly increased (p less than 0.05). His well-being seemed to have improved on this substitutive remedy. Hitherto unrevealed these findings on LPI indicate that carnitine has a lysine-sparing effect and suggest that there might be a biosynthetic pathway of carnitine directly from free lysine in human.

Gyrate atrophy of the choroid and retina. The ocular disease progresses in juvenile patients despite normal or near normal plasma ornithine concentration

Hyperornithinemia disappeared in three children with Gyrate atrophy of the choroid and retina during a low-arginine diet for 3 to 4 1/2 years. Because of the young age of the patients, we had an exceptional opportunity to follow the progression of the disease during this period. Despite the excellent biochemical control, electroretinographic changes progressed in two patients, and the chorioretinal atrophy progressed steadily in all the patients throughout the diet. Dark adaptation and color vision remained stable. In these patients, the normo-ornithinemia has not been able to halt the progression of the chorioretinal degeneration.

Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome: low creatine excretion and effect of citrulline, arginine, or ornithine supplement

Two patients with neonatal onset of hyperornithinemia-hyperammonemia-homocitrullinuria syndrome were studied at 4 and 2 1/2 yr of age, respectively. The aim of the investigation was to assess the effect of supplementing citrulline, arginine, or ornithine (2 mmol/kg per day) while on a protein-restricted diet. The peroral supplementation was carried out during 2 wk for each amino acid. While ammonia in plasma was not increased the supply of citrulline or arginine led to a reduction of plasma glutamine compared to ornithine supplement or to no supplement (control period). Plasmatic ornithine was raised in all instances. Homocitrulline excretion was lower with all additions compared to the control period. Adding citrulline to the diet (in contrast to supplementing arginine) did not lower tubular lysine reabsorption. A lowered creatine excretion was found which could be normalized by arginine or citrulline. The data are compatible with a product inhibition of arginino-glycine transamidinase suggesting that the enzyme is not located in the mitochondrial matrix in man. Citrulline supplement combined with a protein-restricted diet appears to allow a normal development. The additional finding of a factor VII and X deficiency in one of the patient and reports in the literature of this association in two other patients with hyperornithinemia-hyperammonemia-homocitrullinuria syndrome suggest that the genetic defect leading to the syndrome might be located on chromosome 13.

The effect of diet on the ophthalmological, clinical and biochemical aspects of Richner-Hanhart syndrome: a morphological ultrastructural study of the cornea and the conjunctiva

Type II tyrosinemia (Richner-Hanhart syndrome) is a familial aminoacid disorder, clinically characterized by ocular changes (keratitis), palmo-plantar hyperkeratosis, no constant mental changes with mental deterioration, abnormal urinary excretion and high serum tyrosine level in consequence of the absence of tyrosine-aminotransferase. Almost 20 families have been described in the literature of which 50% are of Italian origin, suggesting that this disorder is particularly frequent in our country. We report a family with 2 affected members with typical clinical and biochemical findings (keratitis, palmo-plantar hyperkeratosis, abnormal urinary and serum tyrosine concentrations), not suffering from mental retardation. Clinical symptoms completely disappeared after the decrease of urinary and serum tyrosine levels following a tyrosine- and phenylalanine-free diet. These cases are compared with those reported in literature, and the usefulness of diet for the improvement of clinical and metabolic symptoms is discussed.

Profound neurological illness, relieved by protein restriction, in a baby with a transient disturbance in the metabolism of ingested isoleucine

An 8-month-old infant presented because of poor development followed by the acute onset of cortical blindness and a severe seizure disorder at the time of changing from breast to formula feeding. Metabolic investigations revealed an increased urinary excretion of 2-methyl-3-hydroxybutyric, methylmalonic and 2-ethylhydracrylic acids. The concentration of these compounds in urine was augmented by oral protein (5 g/kg per day) and isoleucine loading. A low protein diet (1.5 g/kg per day) produced a dramatic response with complete cessation of seizures and a marked improvement in vision and general development. After many months of low protein diet, the biochemical abnormalities were no longer detectable, even after protein loading. Extensive investigations have failed to reveal an intrinsic enzyme defect which would account for these clinical and biochemical findings. A toxic effect of a bacterial metabolite of isoleucine is proposed.

Clinical, biochemical and enzymatic studies in type I hyperprolinemia associated with chromosomal abnormality

A severe mentally retarded infant with type I hyperprolinemia associated with chromosomal abnormality is reported. The patient had a characteristic facial appearance of hyperprolinemia and suffered from convulsions after the age of 10 months. The child developed severe mental and motor retardation. The karyotype of the patient revealed partial duplication of the short arm in chromosome 10 using G banding techniques. The patient and her mother showed a fasting hyperprolinemia and an abnormal clearance curve after the proline load in the serum. The proline oxidase activities of the liver tissues obtained by biopsy in the patient was about 9% of those of controls. Kinetic studies and mixed experiments of the enzyme were with normal limits. Restriction of dietary proline at the age of 12 months revealed a prompt fall of the plasma levels of proline to the normal range, and a low proline diet was continued until the present time. During the period of dietary treatment, growth was satisfactory, but her mental development did not improve. From the developmental patterns of proline oxidase activities postnataldy, we speculated that restriction of dietary proline intake should be relieved with age.

N-acetylaspartic aciduria due to aspartoacylase deficiency--a new aetiology of childhood leukodystrophy

We describe a male infant with psychomotor retardation and leukodystrophy who excretes large quantities of N-acetylaspartate in his urine. A high CSF/plasma concentration ratio of N-acetylaspartate indicates that this substance originates in the brain. Fibroblasts from the patient are deficient in aspartoacylase activity. It is proposed that the dysmyelination in the patient may be due to failure of N-acetylaspartate to serve as a carrier of acetyl groups from mitochondria to the cytosol for lipogenesis.

3-Hydroxy-3-methylglutaric aciduria: response to carnitine therapy and fat and leucine restriction

A female infant, born to first cousin parents, lapsed into coma with severe metabolic acidosis on day three of life. The gas chromatographic/mass spectrometric urinary organic acid profile showed marked elevation of the leucine metabolites 3-hydroxy-3-methylglutaric, 3-methylglutaconic, 3-methylglutaric and 3-hydroxy-isovaleric acids. Less than 5% of the normal activity of the enzyme 3-hydroxy-3-methylglutaryl CoA lyase was detected in cultured skin fibroblasts. The patient's total and free carnitine was initially low but rose to normal levels after placing her on DL-carnitine (100 mg kg-1 d-1). On a diet providing 87 mg kg-1 d-1 of leucine and only 25% of total calories as fat and 2 g kg-1 d-1 protein, the concentration of the urinary organic acids fell markedly. She is now 15 months old with normal growth and development. This regimen appears effective in the early treatment of 3-hydroxy-3-methylglutaric aciduria.

Endogenous catabolism is the major source of toxic metabolites in isovaleric acidemia

A patient with isovaleryl-coenzyme A dehydrogenase deficiency was given a synthetic oral feed containing L-(2H3-methyl)-leucine of high isotopic purity as the only dietary precursor to the defective enzyme. Metabolites derived from this source were readily distinguished from their unlabeled endogenous counterparts by mass spectrometry. During 6 consecutive days of labeled leucine ingestion, the average daily excretion of labeled metabolites was only about 10% of the total derived from leucine. It is suggested that therapy should be directed toward the control of endogenous protein turnover rather than the restriction of dietary protein intake.

Anorexia and altered serotonin metabolism in a patient with argininosuccinic aciduria

We studied serotonin metabolism in a metabolically stable 7-year-old girl with argininosuccinic aciduria who had severe anorexia. The CSF concentration of 5-hydroxyindoleacetic acid (HIAA), the metabolite of serotonin, was markedly elevated at 79 ng/ml (normal 33 +/- 11 ng/ml). Altered serotonin metabolism was also reflected in the sleep EEG, which showed decreased REM sleep. Reducing her intake of tryptophan, the precursor of serotonin, from 35 mg/kg/day to 7 mg/kg/day resulted in a decrease in CSF concentration of HIAA to 20 ng/ml and the onset of spontaneous eating for the first time in 4 1/2 years. REM sleep increased from 3% to 9.5% of total sleep time. Two days after increasing tryptophan intake to 25 mg/kg/day, spontaneous feeding stopped, associated with a rise in CSF HIAA to 45 ng/ml. Caloric/carbohydrate intake was found to affect CSF HIAA levels and food intake in an additive manner with tryptophan intake. These observations suggest that altered serotonin metabolism affected feeding behavior in this child, and that this effect could be modified by changing tryptophan or carbohydrate intake.