RESUMO
Las porfirias son la consecuencia de fallas en el metabolismo del hemo. La Porfiria Congénita Eritropoyética (PCE) (enfermedad de Günther) es una porfiria cutánea rara que se transmite en forma autosómica recesiva. Se produce debido a la presencia de mutaciones en el gen de la uroporfirinógeno III sintetasa (UROIII-S) que llevan a una marcada disminución de su actividad y a la producción y acumulación de elevadas cantidades de porfirinas de la serie isomérica I en plasma, tejidos y huesos, responsables de la severa sintomatología cutánea que generalmente presentan los pacientes con esta porfiria. Se han descripto sólo alrededor de 200 casos a nivel mundial. Su expresión clínica es muy heterogénea, encontrándose desde casos muy graves con severo compromiso cutáneo, transfusión-dependiente, hasta casos leves con escasa sintomatología cutánea. Se presentan 5 casos de pacientes argentinos con PCE, 4 infantiles y uno de manifestación tardía, diagnosticados en el Centro de Investigaciones sobre Porfirinas y Porfirias (CIPYP), que constituyen, hasta el momento, los únicos registrados en Argentina. Se encontraron elevadas cantidades de porfirinas en plasma, sangre, orina y materia fecal y un patrón de porfirinas con predominio de la serie I. La actividad de la UROIII-S estaba reducida en un 25-44% con respecto al valor normal. El diagnóstico certero y precoz de esta porfiria es fundamental para aplicar tempranamente el tratamiento adecuado en cada caso y brindarle al paciente una mejor calidad de vida.
Porphyrias are metabolism disorders caused by a partial deficiency in one of the heme biosynthetic pathway enzymes. Congenital Erythropoietic Porphyria, also termed Günther disease, is extremely rare and is inherited as an autosomal recessive trait that results from the markedly deficient activity of the fourth enzyme in the heme biosynthetic pathway, Uroporphyrinogen III synthase (UROIII-S). This enzyme deficiency leads to an increased production and accumulation of the nonphysiological and phototoxic type I porphyrins responsible for the typical clinical manifestations. The disease severity is markedly heterogeneous, ranging from severe transfusion dependency throughout life to milder adult cases with only cutaneous photosensitivity. Only 200 cases have been described all over the world so far. In this work five Argentinean CEP patients are presented, 4 infantile and one late onset case, diagnosed in the CIPYP which are, as far as it is known, the only cases described in Argentina. Increased amounts of porphyrins were found in plasma, blood, urine and faeces, together with high amounts of the pathogenic type I isomer. Enzyme activity was reduced to 25-44% respect to normal values. Early diagnosis is important for correct treatment so as to prevent the characteristic mutilation of the disease and to improve patient´s life quality.
Assuntos
Humanos , Masculino , Feminino , Recém-Nascido , Lactente , Pré-Escolar , Pessoa de Meia-Idade , Porfiria Eritropoética/diagnóstico , Porfiria Eritropoética/genética , Porfiria Eritropoética/urina , Porfiria Eritropoética/sangue , Argentina , Uroporfirinogênio III Sintetase , HemeRESUMO
Transferrin receptors are used by rapidly dividing tissues such as bone marrow for the extraction of iron necessary for their metabolic requirements. As cells in the erythropoietic series mature, transferrin receptors are cleaved from the cell surface and may be measured free in the plasma. Serum transferrin receptors (STR) levels are therfore believed to reflect the extent of erythropoiesis and are elevated in anaemias associated with iron deficiency, haemolysis and thalassaemia and decreased in aplastic anaemia. Levels have been measured in stored sera from 182 children with homozygous sickle-cell (SS) disease and 42 controls with a normal haemoglobin (AA) genotype age 8 years (ñ 3 months) in a cohort study from birth. Levels is SS children (mean, SD: 38.3, 12.7) greatly exceeded those in AA controls (6.7, 1.9) (test = 32.1, p0.001) and were negatively correlated with total haemoglobin and foetal haemoglobin levels in both sexes but not with reticulocyte counts. The serum transferrin receptor level may be a useful indicator of the degree of eryreticulocyte counts. The serum transferrin receptor level may be a useful indicator of the degree of erythropoietic expansion in SS disease, and requires further study to determine its clinical value (AU)