RESUMO

In a new study, LeBlanc and co-workers have discovered an unusually complex dentition in a fossil relative of the modern-day tuatara that features compound occlusal surfaces, thick and prismatic enamel, and a novel enamel-to-bone tooth attachment. This finding suggests that complex dentitions arose independently in several reptilian lineages.

Assuntos

Assuntos

RESUMO

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.

Assuntos

RESUMO

We found that more than 50% of premature infants have elevated plasma ammonium levels during the first 2 months of life. Ammonium levels were twice normal and were unaccompanied by clinical symptoms of vomiting or lethargy. Ten of these infants were given supplements of arginine (1 to 2 mmol/kg/day PO) for 1 to 2 weeks preceded and followed by control periods. In each infant, plasma ammonium levels fell significantly within 2 days of start of arginine supplementation, and increased once arginine was discontinued. We studied 59 additional premature infants, of whom 26 had normal ammonium levels and 33 were hyperammonemic. Plasma arginine and ornithine levels were significantly lower in the hyperammonemic group, but there was no difference in urinary excretion of arginine or ornithine between groups. Half of the hyperammonemic infants received arginine supplementation between 2 and 8 weeks of age. Plasma ammonium levels in the arginine group was 33 + 1 mumol/L., compared to 45 + 2 mumol/L in the untreated group. Follow-up at 18 months of age showed similar IQ scores in all groups, suggesting that significant neurologic deficits do not result from this transient metabolic defect. The mechanism of the hyperammonemia is unclear.

Assuntos

RESUMO

We describe two boys, presenting by 1 year of age, with developmental delay from birth, mildly coarse facial features, and hepatomegaly. These clinical features were most suggestive of a mucopolysaccharidosis, particularly MPS II. Biochemical studies, including sulfate incorporation in fibroblasts and lysosomal enzyme analyses in fibroblasts, leukocytes, and serum, showed abnormalities in both sulfatide and mucopolysaccharide metabolism and led to the diagnosis of multiple sulfatase deficiency. With time, both patients developed an ichthyotic rash and profound intellectual deterioration. We conclude that findings in the first year of life in some patients with MSD may closely resemble those in patients with a MPS disorder rather than the late infantile form of metachromatic leukodystrophy, as is classically described. Thus, MSD should be considered in the young patient suspected of having a MPS disorder.

Assuntos

RESUMO

An infant boy is described whose clinical findings include congenital ascites, hepatosplenomegaly, postnatal growth failure, dysostosis multiplex, delayed development, pericardial effusion, and the nephrotic syndrome. Death occurred before he reached 2 years of age. Evidence indicates that these abnormalities resulted from an autosomal recessive inherited deficiency of neuraminidase.

Assuntos

RESUMO

Two infant siblings with modest elevations of serum phenylalanine concentrations had seizures and developmental regression: they died in their second year. Dihydropteridine reductase activity, which can be measured in normal cultured skin fibroblasts, was measured in the younger sibling and was absent. Parents of the two siblings and parents of a previously reported patient all showed 50% or less of the normal dihydropteridine reductase activity in their cultured fibroblasts. Dihydropteridine reductase activity is also present in normal cultured amniotic fluid cells, offering the possibility of prenatal diagnosis. Absence of dihydropteridine reductase results not only in a defect in the conversion of phenylalaning to tyrosine, but also in the biosynthesis of the neurotransmitters, dopamine, norephinephrine, and serotonin. Since deficiencies in these neurotransmitters would not be alleviated by a phenylalanine-restricted diet, it is important to establish the nature of the enzymatic defect in all suspected variants of phenylketonuria.

Assuntos

RESUMO

A three-year-old boy has coarse facial features, upper respiratory congestion, profound mental retardation, hepatosplenomegaly, increased height and head circumference, cataracts, a gibbus deformity, radiographic changes of dysostosis multiplex, and vacuolized peripheral lymphocytes. These findings are the most commonly reported clinical features in the previously described patients with mannosidosis. Our patient has a severe deficiency, and his parents have intermediate levels, of the acidic component of alpha-mannosidase in their cultured fibroblasts.

Assuntos