RESUMO
Hemoglobin H disease was diagnosed prior to the twenty-second week of gestation in a pregnancy at risk for homozygous alpha-thalassemia using the technique of DNA-DNA hybridization. Fetal DNA was obtained from amniotic fluid fibroblasts obtained during the thirteenth week of gestation and grown in culture. The fetal fibroblast DNA was hybridized to radioactive alpha-globin cDNA. The number of alpha-globin genes present in the fetus was determined by comparing results of hybridization studies on the fetal DNA to similar studies on subjects with well-defined alpha-thalassemia syndromes and with normal subjects. The diagnosis of hemoglobin H disease was confirmed at birth by studies of the cord blood. This study confirms the ability of DNA-DNA hybridization techniques to distinguish the three-gene defect of hemoglobin H disease from the lethal four-gene defect of homozygous alpha-thalassemia.
Assuntos
Hemoglobina H , Hemoglobinopatias/diagnóstico , Hemoglobinas Anormais , Diagnóstico Pré-Natal , alfa-Globulinas , Líquido Amniótico , DNA , Feminino , Sangue Fetal , Fibroblastos , Hemoglobinopatias/genética , Homozigoto , Humanos , Recém-Nascido , Masculino , Hibridização de Ácido Nucleico , Gravidez , Talassemia/diagnóstico , Talassemia/genéticaAssuntos
Hemoglobina Fetal , Hemoglobinas Anormais , Sequência de Aminoácidos , População Negra , Sangue , Cromatografia em Gel , Eletroforese em Gel de Amido , Hemoglobina Fetal/isolamento & purificação , Hemoglobinas Anormais/isolamento & purificação , Humanos , Lactente , Jamaica , Masculino , Cordão UmbilicalRESUMO
A Gy-chain variant, Hb F Port Royal, with an electrophoretic mobility intermediate between Hb S and Hb C was found in a Jamaican-Negro infant, and made up to 14-15 percent of the total Hb F. A glycinamidation procedure was employed to aid in the determining the amino-acid residu substitution of gamma 123 Glu leads to Ala, and the presence of glycine in position 136. (AU)