Genotype and natural history in unrelated individual with phenylketonuria and autistic behavior

We describe three unrelated individuals, two males (ages 35 and 9) and a female (age 8) presenting with late diagnosed phenylketonuria (PKU) and autistic behavior, all showing poor adhesion to the dietary treatment resulting in high plasmatic phenylalanine levels, particularly in the oldest subject. Clinical findings included hair hypopigmentation, microcephaly, severe mental retardation with absent development of verbal language and autistic symptoms in all three patients, whereas variable neurological signs such as seizures, spasticity, ataxia, aggressivity, and hyperactivity were individually found. Homozygosity for the IVS10nt11g/a (IVS10nt546) was found in all. This is the first report of molecular findings in subjects with PKU also presenting with autistic features. The authors discuss if this mutation is particularly involved in the association of autistic symptoms in untreated PKU individuals.

Descrevemos três indivíduos não aparentados, dois do sexo masculino (com idades de 35 e nove anos) e um do sexo feminino (com idade de oito anos) apresentando fenilcetonúria diagnosticada tardiamente e comportamento autístico, todos com adesão limitada ao tratamento dietético resultando em altos níveis plasmáticos de fenilalanina, especialmente no indivíduo mais velho. Os achados clínicos incluem hipopigmentação de cabelos, retardo mental grave com ausência de desenvolvimento da linguagem verbal e sintomas autísticos nos três pacientes, enquanto outros achados neurológicos como convulsões, espasticidade, ataxia, agressividade e hiperatividade são descritos em um indivíduo, cada. Homozigose para a mutação IVS10nt11g/a (IVS10nt546) foi encontrada em todos. Este é o primeiro relato de achados moleculares em indivíduos com fenilcetonúria que desenvolveram características autísticas. Discute-se se essa mutação estaria particularmente envolvida no desenvolvimento de sintomas autísticos em indivíduos com fenilcetonúria não tratada.

HD is beneficial for enzymatic conversion of some amino-acids in the elderly

Many different causes of abnormal amino acid profile in uremic patients including: inadequate nutritional intake, uremic disturbances in amino acid metabolism, loss or fibrosis of renal tissues, metabolic acidosis and hormonal derangement. Some of these factors; such as metabolic acidosis are particularly corrected with dialytic therapy; but others such as decreased intake or hormonal disturbances may persist or worsen after initiation of dialysis. This study was done to investigate the plasma amino acids profile in uremic elderly patients. The present study was carried out on three matched groups: [G1] on HD, [G2] CRF and a control. A significant uniform decrease of Threonine, Valine and Leucine in both HD and CRF. However, a peculiar situation of significant increase in phenylalanine in HD in comparison to CRF and to control. This is similar to the significant increase of Arginine in HD group in comparison to the others. In contrast, phenylalanine was significantly decreased in CRF in comparison to both HD group and the control. The latter was similar to the decrease of Leucine in CRF in comparison to the other two groups. Hence, Phenylalanine was the only AA that was found to be significantly increased in HD and significantly decreased in CRF in comparison to control. Moreover, only Phenylalanine and Arginine were significantly increased in HD group in contrast to the rest of the essential amino-acids, which showed either decrease or no change. Tyrosine and lysine were significantly lower in pre -dialysis CRF group in comparison to patients on HD and the control. This may imply that HD can correct the deficiency of tyrosine and lysine in uremic patients probably due to less inhibition of phenylalanine hydrorxylase. Inter-conversion of phenylalanine to tyrosine was reported to be impaired in CRF; whereas tyrosine metabolism per se does not seem to be grossly affected by uremia. However; Serine was significantly lower in both groups of uremic patients in the current study compared with the control group, with no significant difference in-between pre -dialysis patients and patients on HD. In conclusion, our study showed that HD may be beneficial in restoring the enzymatic turnover of certain amino-acids including: Phenylalanine hydroxylase to normalize tyrosine plasma level, Arginine synthetase to convert citrulline to Arginine. On the other hand, HD may be injurious to the production of other amino-acids like serine due to complete lost of the renal tissue that is responsible of its production from glycine

Fenilquetonuria de diagnóstico neonatal y lactancia materna / Phenylketonuria diagnosed during the neonatal period and breast feeding

Phenylketonuria (PKU) is due to of a defect in the phenylalanine hydroxylase gene (12q22-24.1) leading to hyperphenylalaninemia. Treatment consists in a low phenylalanine (Phe) diet. Aim: To evaluate the evolution of early diagnosed PKU children, receiving direct breast feeding, and a special formula without Phe, during their first six months of life. Patients and methods: Nineteen PKU children diagnosed in the neonatal period (19.29±13.8 days of age), treated with breast feeding and formula without Phe since diagnosis, were studied. Intake of calories, proteins and dietary Phe were quantified. Blood Phe, nutritional status and psychomotor development were also measured. Results: The diet that these children received during the 6 months period of study, had a mean of 127±19.9 Kcal/kg/day, 1.95±0.3 g protein/kg/day and 35.3±9.5 mg Phe/kg/day. Fifteen children maintained the blood level of Phe under 8 mg/dl, considered an excellent metabolic control. Only 4 cases had intermittently high levels, between 10-12 mg/dl. At 6 months of age, 74% of the children maintained breast feeding as the only source of Phe. Sixty three percent had a normal nutritional status, 5.2% were at nutritional risk and 31.6% were overweight. Eighty one percent had a normal mental development. Conclusions: The use of direct breast feeding allows a good metabolic control and improves growth and development of early diagnosed PKU children (Rev Méd Chile 2003; 131: 1280-87).

Hepatic phenylalanine-hydroxylase and tyrosine-aminotransferase mRNA levels in rats adapted to diets with different concentrations of protein

Se estudió el efecto de la concentración de la proteína de la dieta sobre concentraciones de ARNm de la tirosina aminotransferasa (TAT) y la fenilalanina hidroxilasa (PAH) hepáticas en ratas adaptadas a consumir dietas con 18 ó 50 por ciento de caseína en un horario restringido de 7 horas (9 a 16 h) durante 5 días. Las concentraciones de ARNm de TAT de ratas adaptadas a una dieta de 18 por ciento de caseína y alimentadas en forma aguda con dietas que contenían 6, 18 ó 50 por ciento de caseína, fueron 0.15, 0.84 y 5.08 veces más altas a las 6 horas en comparación con las concentraciones de ARNm antes de la administración de la dieta. Las concentraciones de ARNm de TAT después de 17 horas de ayuno en las ratas alimentadas con 6, 18 ó 50 por ciento de caseína fueron respectivamente -0.45, 1.76 y 9.11 veces mayores en comparación con el valor basal. Las concentraciones ARNm de PAH mostraron un patrón similar; en las ratas adaptadas a 18 por ciento de caseína se observó un aumento de -.68, 1.63 y 2.5 veces en las concentraciones de ARNm de PAH en las ratas alimentadas en forma aguda con 6, 18 y 50 por ciento de casína respectivmanete y un aumento de -0.86, 2.32 y 9.33 veces después de 17 horas de ayuno. La concentraciones de ARNm de TAT y PAH en ratas adaptadas a consumir 50 por ciento de caseína y luego alimentadas con 6 ó 50 por ciento de caseína mostraron un pico máximo a las 6 horas de ayuno. Estos resultados sugieren que las concentraciones crecientes de proteína en la dieta son capaces de producir aumentos en la concentración de los ARNm de las dos enzimas, posiblemente para eliminar el exceso de aminoácidos consumidos, ya que la concentración de los ARNm dependió más del contenido de proteína de la dieta de adaptación

Seguimiento de pacientes con hiperfenilalaninemia diagnosticados precozmente / Follow-up of patients with early diagnostic of hyperphenylalaninemia

Se presentan 17 pacientes con hiperfenilalaninemia diagnosticados en el período neonatal (20,3 ñ 12,6 días de vida), cuyas concentraciones iniciales de fenilalanina sérica eran de 16,5 a 46,2 mg por ciento. En todos el tratamiento dietético comenzó al hacer el diagnóstico y han sido seguidos en un policlínico especial del Instituto de Nutrición y Tecnología de los Alimentos de la Universidad de Chile. Se describen la dieta, los suplementos de minerales y vitaminas requeridos, que han permitido, durante el seguimiento, mantener concentraciones de fenilalanina en el suero entre 2 y 6 mg/dl, salvo transgresiones transitorias que han ocurrido en 2 casos. En 82,2 por ciento de los casos el crecimiento y el desarrollo han sido normales. Se subraya la importancia de tomar la primera muestra en tarjet de papel filtro a todos los recién nacidos antes de cumplir 10 días de vida, para hecer oportunamente el diagnóstico. Los programas se seguimiento integral facilitan el manejo y el desarrollo físico y mental normales de estos niños