Agne Larsson

Psychological Reactions in 102 Families with a Newborn Who Has a Falsely Positive Screening Test for Congenital Hypothyroidism

The potential psychological risks of falsely positive test results in neonatal screenings have not been studied previously. 20000 newborns were screened for congenital hypothyroidism. Of the 144 positive tests, 137 were false. The families of 102 babies with false positives were explored in reference to their (1) initial parental psychic reactions (emotional reactions and abilities for coping) and (2) residual reactions 6 to 12 months later. 78 families initially exhibited strong emotional reactions. Providing information about a positive screening test is therefore an acute strain to the majority. After a period of 6 to 12 months there was in 18 families persistent insecurity regarding the babys health. These concerns were linked by the family to the screening and the disease screened for. This may impair the parent–child relation and, thus, the childs development. Thus a false positive test appear to trigger in the majority a development of a psychic crisis. 12 families seemed however to have been totally untouched by the potential threat of the information. The crisis is effectively solved by most (consideration must be paid to the integrated psychological support given to all). It is not known whether the 18 risk families actually have been iatrogenically hurt or if their worries brought to attention in connection with the screening merely represent habitual psychic maladjustment.

CONGENITAL HYPOTHYROIDISM IN SWEDEN Incidence and Age at Diagnosis

ABSTRACT. A total number of 112 children with congenital hypothyroidism were diagnosed in all Childrens Hospitals and Pediatric Wards in Sweden during the 7‐year period 1969–1975. Since it may be assumed that all cases of congenital hypothyroidism, which were diagnosed during that period were seen in one of these hospitals, the incidence of congenital hypothyroidism in Sweden can be calculated to be 1:6900 live births. In spite of an efficient National Health Care Program for Infants the diagnosis was delayed until after an age of three months in 52% of the cases. This fact supports the view that mass screening of newborns for congenital hypothyroidism has to be introduced in Sweden. However, the beneficial effects of such a program cannot be fully elucidated until it has been considered whether earlier instituted treatment would have improved the outcome of children in whom a diagnosis was made after 3 months of age.

Inhibition of γ-glutamylcysteine synthetase by cystamine; An approach to a therapy of 5-oxoprolinuria (pyroglutamic aciduria)

Abstract γ-Glutamylcysteine synthetase is strongly inhibited by cystamine; thus, 20 μM cystamine inhibited the activity by 50%. Inhibition is rapid and the inhibited enzyme is reactivated by dithiothreitol suggesting that cystamine reacts with an enzyme sulfhydryl group. Inhibition by cystamine is not prevented by MgATP, L-α-aminobutyrate, or L-glutamate suggesting that cystamine may not interact at the active site. Little or no inhibition was observed with N,N′-diacetyl cystamine, L-cystine, glutathione disulfide, 2-hydroxyethyl disulfide, and thioglycolate disulfide, whereas thiocholine disulfide produced moderate inhibition. Cystamine or an inhibitory analog of cystamine might be useful in the therapy of the disease 5-oxoprolinuria in which there is an overproduction of γ-glutamylcysteine.

Glutathione and γ-glutamylcysteine in whole blood, plasma and erythrocytes

Abstract A method for the simultaneous determination of glutathione and γ-glutamyl-cysteine in capillary blood samples is described. The whole blood levels of glutathione and γ-glutamylcysteine are 1.09 ± 0.20 mmol/l and 25 ± 8 μ mol/l (M ± S.D.), respectively. The plasma concentration is approximately 4 μmol/l for both compounds. It is important to treat the blood samples with a reducing agent before protein precipitation to release glutathione and γ-glutamylcysteine from disulfide linkages since, otherwise, 30–40% of the glutathione and 80% of the γ-glutamylcysteine is lost with the protein precipitate. Whole blood is preferable to washed erythrocytes for the analysis since the washing procedure involves losses of, especially, γ-glutamyl-cysteine.

PYROGLUTAMIC ACIDURIA Studies in an Infant with Chronic Metabolic Acidosis

A one‐year‐old girl with chronic metabolic acidosis was found to have normal renal acidi‐fication. In the urine, however, she excreted a daily amount of 50 mmoles of L‐pyroglutamate (5‐oxo‐˜‐proline). This excretion did not increase with increasing protein intake. Studies of the turnover of L‐pyroglutamate under steady state conditions revealed that 75% of the pyroglutamate synthesized was metabolized by the patient. The level of pyroglutamate degrading enzyme (5‐0times0‐prolinase) in the patients leucocytes was not decreased, and the enzyme appeared to have normal affinity for its substrates, i.e. pyroglutamate and ATP.

5-OXOPROLINURIA DUE TO HEREDITARY 5-OXOPROLINASE DEFICIENCY IN TWO BROTHERS–A NEW INBORN ERROR OF THE γ-GLUTAMYL CYCLE

ABSTRACT. Larsson, A., Mattsson, B., Wauters, E. A. K., van Gool, J. D., Duran, M. and adman, S. K. (Department of Paediatrics, Karolinska Institute, St. Gorans Childrens Hospital, Stockholm, Sweden, and University Childrens Hospital, “Het Wilhelmina Kinderziekenhuis”, Utrecht, The Netherlands). 5‐Oxoprolinuria due to 5‐oxoproIinase deficiency in two brothers–a new inborn error of the γ‐glutamyl cycle. Acta Paediatr Scand, 70:301, 1981.–Two brothers, aged 16 and 11 years, had recurrent episodes of vomiting, diarrhoea and abdominal pain, starting in infancy. In spite of extensive investigations no cause of their enterocolitis could be established. After several years symptomatic treatment was discontinued without any recurrence of symptoms. Their father and several paternal relatives have had kidney stones. Both boys developed urolithiasis and an oxalate‐containing stone was removed from the elder brothers kidney. He had no hypercalciuria. His glomerular and tubular function tests were normal. Gas chromatography of urine from both brothers revealed massive excretion of L‐5‐oxoproline (pyroglutamic acid). Glutathione levels in erythrocytes of both patients were normal. The activities of enzymes of the γ‐glutamyl cycle were analysed in erythrocytes, leukocytes and cultured skin fibroblasts. The level of glutathione synthetase was normal, as was the affinity of this enzyme for its substrate γ‐glutamyl‐cysteine. Feedback inhibition of γ‐glutamyl‐cysteine synthetase by glutathione was also normal. Both patients had a specific deficiency of 5‐oxoprolinase, the activity of which was 2‐A % of that of control subjects. Their parents had intermediate 5‐oxoprolinase activities in fibroblasts, indicating a recessive mode of inheritance. Thus, 5‐oxoprolinuria in these two patients was due to a lack of S‐oxoprolinase, i.e., a new inborn error in the γ‐glutamyl cycle.

Erythrocyte glutathione synthetase in 5-oxoprolinuria: Kinetic studies of the mutant enzyme and detection of heterozygotes

The primary metabolic defect in 5-oxoprolinuria is a generalized deficiency of glutathione synthetase. The activity of this enzyme was determined in cell-free extracts of erythrocytes from patients with 5-oxoprolinuria, their parents and a sibling as well as from normal control individuals. The following activities (pkat/mg of hemoglobin) for glutathione synthetase were obtained: homozygotes mean 0.10 (range 0.07-0.12), heterozygotes mean 3.1 (range 2.8-3.7) and control individuals mean 6.1 (range 5.4-6.7). These results indicate that 5-oxoprolinuria, i.e. the defective gluthione synthetase gene(s), is transmitted by autosomal recessive inheritance. Studies of the kinetics of the low remaining activity of erythrocyte glutathione synthetase in patients with 5-oxoprolinuria failed to reveal defective affinity for glycine, gamma-glutamyl-alpha-aminobutyrate, ATP and Mg2+ ions. Furthermore, the pH optimum, time curves and temperature dependence for the mutant enzyme activity did not significantly differ from the corresponding parameters observed with normal enzyme.

CONGENITAL HYPOTHYROIDISM IN SWEDEN Psychomotor Development in Patients Detected by Clinical Signs and Symptoms

Abstract. Aim, J., Larsson, A. and Zetterström, R. (Department of Paediatrics, Karolinska Institute, St. Görans Childrens Hospital, Stockholm, Sweden). Congenital hypothyroidism in Sweden: Psychomotor development in patients detected by clinical signs and symptoms. Acta Paediatr Scand, 70: 907, 1981. Thirty‐nine children at 7 to 9 years of age with congenital hypothyroidism have been studied with respect to their intellectual, neurological and social functions. Their intellectual achievement as assessed by the WISC test, was significantly lower than in a reference population (mean IQ88, range 50–113). In children who showed signs and symptoms of hypothyroidism during their first four weeks of life, there was a negative correlation between the age when therapy was started and intellectual development. No such correlation was found in children who showed signs and symptoms after the first four weeks of life. Nine children of 26 with signs of hypothyroidism in the neonatal period, were found to have neurological abnormalities consisting of fine and gross motor disturbances. The neurological abnormalities seriously affected daily life in only the two most severely mentally retarded. No correlation was found between the age when the therapy was started and neurological abnormalities. Three children attended special schools because of mental retardation and six attended normal schools but required additional teaching assistance for learning disabilities. Our results suggest that the risk of future intellectual handicaps may be reduced by early treatment in children with hypothyroidism presenting during the neonatal period.

On the mechanism of 5-oxoproline overproduction in 5-oxoprolinuria

The primary metabolic defect in 5-oxoprolinuria (pyroglutamic aciduria) is the lack of glutathione synthetase. The mechanism of the concomitant overproduction of 5-oxoproline was studied using cell-free extracts of erythrocytes from control individuals and from patients with 5-oxoprolinuria. Such extracts catalyzed the synthesis of 5-oxoproline from L-glutamate. Addition of ATP, Mg ions and alpha-aminobutyrate was needed for optimal activity. The conversion of glutamate to 5-oxoproline occurred in two steps, catalyzed by gamma-glutamyl-cysteine synthetase and gamma-glutamyl cyclotransferase, respectively. Extracts of erythrocytes from control subjects and patients with 5-oxoprolinuria had identical capacity to synthesize 5-oxoproline. The conversion of glutamate to 5-oxoproline was markedly inhibited by reduced glutathione, which exerted its effect on the gamma-glutamyl-cysteine synthetase step. The following mechanism is postulated for the overproduction of 5-oxoproline in 5-oxoprolinuria: the deficiency of glutathione synthetase causes a lack of glutathione which is an essential feed-back inhibitor in the initial step of its biosynthesis. Therefore gamma-glutamyl-cysteine is produced in excessive amounts and it is subsequently converted to 5-oxoproline (and cysteine) by gamma-glutamyl cyclotransferase. This overproduction of 5-oxoproline exceeds the capacity of the 5-oxoprolinase and 5-oxoproline accumulates in body fluids.

KETOTIC HYPOGLYCEMIA OF CHILDHOOD—A CLINICAL TRIAL OF SEVERAL UNIFYING ETIOLOGICAL HYPOTHESES

ABSTRACT. Dahlquist, G., Gentz, J., Hagenfeldt, L., Larsson, A., Löw, H., Persson, B. and Zetterström, R. (Department of Paediatrics, St. Görans Childrens Hospital, the Department of Clinical Chemistry and the Department of Endocrinology, Karolinska Hospital, Stockholm, Sweden). Ketotic hypoglycemia of childhood—a clinical trial of several unifying etiological hypotheses. Acta Paediatr Scand, 68: 649, 1979.—We have studied 15 children referred to St. Görans Childrens Hospital because of suspected ketotic hypoglycemia. The patients were investigated according to a program designed to test several hypotheses—old and new—postulated to explain the etiology of ketotic hypoglycemia. We have used the classical ketogenic provocation with a low calorie, high fat diet and measured the blood levels of several substrates and hormones as well as the urinary excretion of certain metabolites and hormones. Out of the 15 children, 6 will fill the criteria of ketotic hypoglycemia at the time of study. The most remarkable finding in these 6 children in contrast to the other children studied was that they did not decrease their peripheral glucose utilization (measured as Kg) during starvation. These 6 children seemed to be more “advanced” in their adaptation to ketogenic diet in all other parameters studied. The children with ketotic hypoglycemia did not differ from the other children in plasma level of cortisol or urinary excretion of nitrogen, urea, 3‐methylhistidine and catecholamines. We favour the concept that the children with ketotic hypoglycemia represent the tail of the gaussian curve in the normal age‐dependent development of the adaptation to starvation.