RESUMEN

Pseudodeficiency is defined as the in vitro measurement of low activity (usually under 15% of the normal mean for controls) of an enzyme in a healthy person. They may be hard to distinguish from presymptomatic people who will present with adult-onset clinical disease. The finding of healthy people with low arylsulfatase A and galactocerebrosidase activities is well documented. This confuses the laboratory doing testing and the clinician providing the sample. Therefore confirmation of a diagnosis of metachromatic leukodystrophy and Krabbe disease, as well as accurate identification of carriers, requires additional testing including 14C-sulfatide loading in cultured skin fibroblasts, examination of urine for excretion of undegraded lipids, examination of enzyme levels in additional family members including grandparents, and molecular analysis of DNA samples for known mutations.

Asunto(s)

Cerebrósido Sulfatasa/análisis , Galactosilceramidasa/análisis , Leucodistrofia de Células Globoides/diagnóstico , Leucodistrofia Metacromática/diagnóstico , Adulto , Células Cultivadas , Cerebrósido Sulfatasa/deficiencia , Cerebrósido Sulfatasa/genética , Niño , Pruebas Enzimáticas Clínicas , ADN/análisis , Diagnóstico Diferencial , Reacciones Falso Negativas , Femenino , Enfermedades Fetales/diagnóstico , Enfermedades Fetales/enzimología , Fibroblastos/enzimología , Galactosilceramidasa/deficiencia , Galactosilceramidasa/genética , Frecuencia de los Genes , Tamización de Portadores Genéticos , Prueba de Complementación Genética , Humanos , Leucocitos/enzimología , Leucodistrofia de Células Globoides/enzimología , Leucodistrofia de Células Globoides/genética , Leucodistrofia Metacromática/enzimología , Leucodistrofia Metacromática/genética , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Embarazo , Diagnóstico Prenatal