RESUMO
Hereditary elliptocytosis (HE) is a group of hemolytic anemias characterized by the presence of elliptical erythrocytes. The underlying alterations lie in the proteins of the membrane skeleton. Defects of the alphaI domain of spectrin have been defined based on a decrease in the normal 80-kD alphaI domain and a concomitant increase in one or more lower molecular weight peptides. We have studied three Brazilian kindreds with black ancestry, who presented mild common spalphaI/50 HE. Our aim was to determine the molecular alteration responsible for the spalphaI/50 HE observed in these three kindreds and to evaluate the presence and influence of allele alphaLELY in the expression of this type of HE. In order to establish the molecular defect, exons 5, 6 and 11 were amplified and submitted to a nonradioactive single strand conformation polymorphism protocol. An identical band shift in exon 6 was observed in all 3 patients and their affected relatives. Direct sequencing of the amplification products of exon 6 showed the same molecular defect in all patients: a T-->C substitution, responsible for the L260P mutation. Allele alphaLELY, detected by PCR and restriction enzyme digestion, was present in the heterozygous form in the three propositi and was associated in trans with the elliptocytogenic mutation. Blood smears of the patients with HE and alphaLELY in trans showed pronounced elliptocytosis, poikilocytosis and a few small red cell fragments, whereas the blood smears of their relatives, who had HE without allele alphaLELY, showed mild common HE with a predominance of ovalocytes and the absence of poikilocytes. We conclude that allele alphaLELY does not lead to the worsening of clinical conditions when associated in trans with mild HE, but can be easily distinguished by a blood smear analysis. The predominance of the L260P mutation in the kindreds studied could be related to the colonization of Brazil during the slave trade by Africans from the Benin-Togo area, where this mutation is particularly common.
Assuntos
Alelos , Eliptocitose Hereditária/sangue , Eliptocitose Hereditária/genética , Espectrina/genética , Adolescente , Adulto , Brasil , Eliptocitose Hereditária/epidemiologia , Feminino , Humanos , Masculino , Linhagem , Espectrina/biossínteseRESUMO
Using clinical, functional and biochemical criteria, we studied the red blood cell membrane of nine caucasic patients from four families with hereditary elliptocytosis (HE). From a clinical point of view, seven cases were classified as compensated mild HE in whom anemia and splenomegaly are absent and reticulocytosis is slightly elevated or normal. Two cases were uncompensated mild HE with anemia, reticulocytosis, splenomegaly and erythrocytic fragmentation. (Table 1). Three individuals from one family displayed a significant reduction of protein 4.1 by polyacrylamide gel electrophoresis; one of them was uncompensated HE. The patterns of limited tryptic digestion and dimer/tetramer proportion of spectrin were normal. The study of red cell deformability by ectacytometry revealed that the cell deformability under isotonic conditions was decreased in all HE patients and the curve obtained had trapezoidal shape (Fig. 3). We found that the deformability index correlated well with the degree of anemia, but no correlation was observed between clinical findings, morphological phenotype and specific molecular etiology. According to our knowledge, this is the first report on molecular and functional studies in HE in Argentina.
Assuntos
Proteínas do Citoesqueleto , Eliptocitose Hereditária/sangue , Deformação Eritrocítica , Proteínas de Membrana/deficiência , Neuropeptídeos , Adulto , Idoso , Criança , Pré-Escolar , Eletroforese em Gel de Poliacrilamida , Membrana Eritrocítica/metabolismo , Família , Feminino , Citometria de Fluxo , Humanos , Masculino , Espectrina/biossínteseRESUMO
Se estudiaron nueve pacientes (cuatro familias) con eliptocitosis herediataria (EH). Desde el punto de vista clínico, se identificaron dos tipos de presentación: siete pacientes fueron formas compensadas y dos (de 7 y 63 años) pertenecientes a distintas familias mostraron anemia, esplenomegalia, reticulocitosis y fragmentación globular. En una familia se comprobó una disminución del stock total de la proteína 4.1 en la electroforesis de proteína de membrana en gel de poliacrilamida con SDS (SDS-PAGE). Uno de sus miembros se comprobó como forma descompensada. El estudio de dímeros y tetrámeros y la digestión tríptica de espectrina fue normal en todos los casos. En la determinación de la deformabilidad en función de la osmoralidad con el ectacitómetro se halló una buena correlación entre el índice de deformabilidad (ID) y el grado de anemia. De acuerdo a los resultados de este estudio pudimos confirmar la gran heterogeneidad clínica de la EH aún en miembros de una misma familia
Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Criança , Adulto , Idoso , Deformação Eritrocítica/genética , Eliptocitose Hereditária/genética , Proteínas de Membrana/deficiência , Eliptocitose Hereditária/sangue , Citometria de Fluxo , Membrana Eritrocítica/metabolismo , Espectrina/biossínteseRESUMO
Se estudiaron nueve pacientes (cuatro familias) con eliptocitosis herediataria (EH). Desde el punto de vista clínico, se identificaron dos tipos de presentación: siete pacientes fueron formas compensadas y dos (de 7 y 63 años) pertenecientes a distintas familias mostraron anemia, esplenomegalia, reticulocitosis y fragmentación globular. En una familia se comprobó una disminución del stock total de la proteína 4.1 en la electroforesis de proteína de membrana en gel de poliacrilamida con SDS (SDS-PAGE). Uno de sus miembros se comprobó como forma descompensada. El estudio de dímeros y tetrámeros y la digestión tríptica de espectrina fue normal en todos los casos. En la determinación de la deformabilidad en función de la osmoralidad con el ectacitómetro se halló una buena correlación entre el índice de deformabilidad (ID) y el grado de anemia. De acuerdo a los resultados de este estudio pudimos confirmar la gran heterogeneidad clínica de la EH aún en miembros de una misma familia (AU)