[Hemoglobin Haná or alpha 2 beta 2 63 (E7) His-Asn: a new unstable hemoglobin variant with a paradoxically different clinical manifestations in smokers and non-smokers in the same family].

The authors describe the identification and the clinical manifestations of a new structural variant of haemoglobin found in three subjects from two generations of a Moravian family. It is manifested by mild haemolytic anaemia with Heinz bodies in the proband and a slightly elevated value of methaemoglobin. The sequential analysis of the beta-globin gene provided evidence that the cause is mutation CAT-AAT in codon 63 which leads to the exchange of distal histidine /E7/ for asparagine. The ratio of beta X:beta A is 38:62. The mother with the same mutation is asymptomatic. The relative amount of beta X:beta A mRNA transcripts in mother and daughter are equal. This indicates that the clinical differences are not due to a different gene expression. The mother is a heavy smoker with an elevated CO-Hb level that probably protect the mutant against oxidative denaturation and increases thus the stability of Hb-Haná. The authors discuss also the finding of two abnormal stripes assessed by three electrophoretic methods.