Heterozygosity and Homozygosity for the High Oxygen Affinity Hemoglobin Tarrant or α126 (H9) ASP→ASN in two Mexican Families

Abstract

Two Mexican families from Jalisco were studied in which 11 members were carriers of Hb Tarrant. Ten subjects were Hb Tarrant heterozygotes producing .apprx. 25% of the abnormal Hb. One 9 yr old boy was homozygous for Hb Tarrant. About 50% of his Hb was of the variant type. The heterozygotes had mild erythrocytosis; this was considerably more severe in the homozygote. The average P50 value for heterozygotic blood was 15.1 mm Hg (controls: 22.5 mm Hg) and this value decreased to 9 mm Hg in the homozygote. The clinical condition of the homozygote is compatible with a mild chronic tissue hypoxia.