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Antecedentes: la fenilcetonuria clásica es una encefalopatía genética caracterizada por una inhabilidad de los individuos para metabolizar la fenilalanina, por lo que su concentración plasmática se eleva a niveles tóxicos. Clínicamente se manifiesta como irritabilidad, alteración del sueño, indiferencia al medio, crisis convulsivas, retraso del neurodesarrollo, conducta autista, agresividad y discapacidad intelectual. Objetivo: describir los hallazgos y cuantificar el coeficiente de difusión aparente en los estudios de imagen de resonancia magnética de cráneo, de pacientes con fenilcetonuria clásica diagnosticada tardíamente en el Instituto Nacional de Pediatría (México). Materiales y métodos: análisis retrospectivo de imágenes cerebrales obtenidas por resonancia magnética en pacientes con fenilcetonuria clásica. Se utilizó un magneto Signa Excite de 1.5 teslas con antena cerebral de ocho canales de arreglo en fase. Se midió el coeficiente de difusión aparente en la estación de trabajo Advantage Workstation 4.2p. Resultados: en los pacientes se observaron alteraciones en las sustancias blanca, gris, o ambas. En la sustancia blanca las lesiones hiperintensas en el área peritrigonal fueron las más frecuentes; se encontraron alteraciones bilaterales en la sustancia blanca frontal, temporal, occipital, subcortical y periventricular. Se observó disminución del coeficiente de difusión aparente en la sustancia blanca peritrigonal, occipital, cuerpo calloso, ganglios basales y cerebelo. Un paciente tenía dos quistes aracnoideos. Conclusión: todos los pacientes estudiados tuvieron las anormalidades características de la enfermedad en las imágenes de resonancia magnética. Los mecanismos causantes de las lesiones cerebrales en la fenilcetonuria, su distribución espacial y su evolución son poco conocidos y requieren de investigaciones posteriores.

In order to diagnose the nutritional status and to provide a personalized treatment in PKU patients, an evaluation of nutritional status should be conducted. Several components are involved in the nutritional assessment; among the parameters there are anthropometric evaluation: weight, height, head circumference; biochemical: proteins, amino acids, vitamins, inorganic nutrients, essential fatty acids; clinical: deficiencies in hair, skin, oral cavity , eyes, etc.; dietary assessment: quantification of energy intake, macronutrients and micronutrients through several tools such as the 24-hour recall; finally it must be taken into account the interaction of nutrients such as carnitine, fatty acids, vitamin B complex, among others, with drugs, which are often anticonvulsants, in order to plan the diet and prevent a future nutritional deficiency. It is important to perform the nutritional status assessment frequently in patients with PKU because the dietary management is essential to prevent neurological problems.

Argentinean hyperphenylalaninemia newborn screening program was initiated by the Infantile Endocrinology Foundation in 1985. At the present it coexists with other several public health programs. To date phenylketonuria (PKU) incidence is 1:12,000 living newborns out of 1,300,000 subjects tested. Nutritional treatment consists of a diet restricted in phenylanine (Phe) and free of animal food, it is started in all children whose serum Phe levels are above 6 mg/dL, low tyrosine (Tyr) concentration, and a Phe to Tyr ratio >3, although patients between 2 to 6 mg/dL are closely followed. Periodic blood Phe quantification and dietetic instructions to the patient are required in order to keep Phe levels in a safe range that preserves nervous system maturing, and prevention of mental retardation which is inherent to non-treated disease. Educational activities constitute the core of the teamwork; they are destined to achieve the best psycho-social integration of the patient to society. Patients’ mothers are trained to follow dietetic quantities of Phe following the “Practical guidance for phenylketonuric patients’ nutrition”. Diet compliance is a complex process which should be evaluated in individual and familiar context in order to identify the need for extra medical support; adolescents are the most vulnerable age population. It has been noted that late diagnosed patients who were given the adequate proposed treatment improved in terms of neurological symptoms, behavioral issues as well as in their potential for rehabilitation.

The evaluation of neuropsychological development in phenylketonuria patients must be considered in a comprehensive follow-up. This assessment should include all aspects of healthy development, including motor skills. This article outlines the results of a study whose objective was to show the relationship between age at onset of dietary treatment and adherence to the treatment, and the motor behavior of hyperphenylalaninemic children under nine years.

Introduction: Classic phenylketonuria (PKU) is a genetic encephalopathy characterized by impairment of phenylalanine (Phe) metabolism, leading to elevation of blood Phe to toxic levels. Clinical manifestations include irritability, sleep disorders, apathy, seizures, developmental delay, autistic behavior, aggressiveness; mental retardation is the most severe manifestation of the disease. Objective: To describe the findings of brain nuclear magnetic resonance (NMR) and to measure the apparent diffusion coefficient (ADC) of Mexican PKU patients diagnosed by their clinical manifestations in the National Institute of Pediatrics (INP). Material and methods: Retrospective analysis of brain images obtained by NMR from PKU patients. A Signa Excite magnet of 1.5 Tesla with an 8-channel phased array cerebral antenna was used. ADC was measured on the Advantage Workstation 4.2p. Results: Abnormalities in the white and gray matter were observed in all patients; bilateral changes were present in the frontal, temporal, occipital, subcortical and periventricular white matter. ADC was diminished in the peritrigonal and occipital white matter; as well as in the corpus callosum, basal ganglia and cerebellum. One patient had two arachnoid cysts. Conclusion: All PKU patients exhibited the characteristic NMR abnormalities. The mechanisms responsible for brain damage that occur in PKU patients are poorly understood and require further research. [ABSTRACT FROM AUTHOR]

Phenylketonuria is an inborn error of metabolism that causes structural abnormalities in the white matter of the brain. In untreated patients demyelization can be observed, and there is evidence of intramyelin edema even in some treated patients. Imaging studies especially magnetic resonance imaging are useful for the study of patients with phenylketonuria, but their benefit as monitoring tools is controversial.

In order to diagnose the nutritional status and to provide a personalized treatment in PKU patients, an evaluation of nutritional status should be conducted. Several components are involved in the nutritional assessment; among the parameters there are anthropometric evaluation: weight, height, head circumference; biochemical: proteins, amino acids, vitamins, inorganic nutrients, essential fatty acids; clinical: deficiencies in hair, skin, oral cavity, eyes, etc.; dietary assessment: quantification of energy intake, macronutrients and micronutrients through several tools such as the 24-hour recall; finally it must be taken into account the interaction of nutrients such as carnitine, fatty acids, vitamin B complex, among others, with drugs, which are often anticonvulsants, in order to plan the diet and prevent a future nutritional deficiency. It is important to perform the nutritional status assessment frequently in patients with PKU because the dietary management is essential to prevent neurological problems. [ABSTRACT FROM AUTHOR]

Phenylketonuria (PKU) is an innborn error in phenylalanine metabolism. It was first described by Asbjörn Fölling in 1934 in Norway. PKU has been the paradigm of inherited metabolic disorders. It also allowed the proposition for the first biochemical explanation of mental retardation. This prompted the widespread search of this condition in neonates through newborn screening. Unlike developed countries, in Mexico mental retardation is still caused by PKU; therefore it is important to know the history of the problem, the PKU experience in Mexico and future perspectives. [ABSTRACT FROM AUTHOR]

Argentinean hyperphenylalaninemia newborn screening program was initiated by the Infantile Endocrinology Foundation in 1985. At the present it coexists with other several public health programs. To date phenylketonuria (PKU) incidence is 1:12,000 living newborns out of 1,300,000 subjects tested. Nutritional treatment consists of a diet restricted in phenylanine (Phe) and free of animal food, it is started in all children whose serum Phe levels are above 6 mg/dL, low tyrosine (Tyr) concentration, and a Phe to Tyr ratio >3, although patients between 2 to 6 mg/dL are closely followed. Periodic blood Phe quantification and dietetic instructions to the patient are required in order to keep Phe levels in a safe range that preserves nervous system maturing, and prevention of mental retardation which is inherent to non-treated disease. Educational activities constitute the core of the teamwork; they are destined to achieve the best psycho-social integration of the patient to society. Patients' mothers are trained to follow dietetic quantities of Phe following the "Practical guidance for phenylketonuric patients' nutrition". Diet compliance is a complex process which should be evaluated in individual and familiar context in order to identify the need for extra medical support; adolescents are the most vulnerable age population. It has been noted that late diagnosed patients who were given the adequate proposed treatment improved in terms of neurological symptoms, behavioral issues as well as in their potential for rehabilitation. [ABSTRACT FROM AUTHOR]

The evaluation of neuropsychological development in phenylketonuria patients must be considered in a comprehensive follow-up. This assessment should include all aspects of healthy development, including motor skills. This article outlines the results of a study whose objective was to show the relationship between age at onset of dietary treatment and adherence to the treatment, and the motor behavior of hyperphenylalaninemic children under nine years. [ABSTRACT FROM AUTHOR]

Phenylketonuria is an inborn error of metabolism that causes structural abnormalities in the white matter of the brain. In untreated patients demyelization can be observed, and there is evidence of intramyelin edema even in some treated patients. Imaging studies especially magnetic resonance imaging are useful for the study of patients with phenylketonuria, but their benefit as monitoring tools is controversial. [ABSTRACT FROM AUTHOR]