ABSTRACT
We report a 23-year-old man and three members of his family with Hb J-Iran confirmed by electrophoresis, chain separation by high performance liquid chromatography and sequencing. Alpha thalassemia was also confirmed in two family members. The substitution at ß77 led to a higher negative charge of the ßJ-Iran subunit, which enhanced its electrostatic attraction for the normal positively-charged α subunit. Therefore, more Hb J-Iran than Hb A forms in the red blood cells of heterozygotes. In α-thalassemia, the more attractive ßJ-Iran subunit outcompetes ßA subunits in forming assemblies with deficient α subunits, so even more Hb J-Iran was formed.
ABSTRACT
We present the results of screening for pyruvate kinase (PK) deficiency on a cohort of 146 patients pre-selected from 4017 individuals by hematological index analysis. On average the PK activity levels measured in this cohort study were about 1.9% IU/g Hb while the activity measured in 85 healthy adults with normal erythrocyte indexes was in the range of 3.9-9.8 IU/g Hb. We were able to define 14 different mutations in the coding sequence of the R-PK gene in 74 individuals with low enzyme activity. The most common were the G1168A and G1529A mutations at exon 11 occurring in 54% of the cases. Other mutations occurring more than once were C1492T, C1456T, G1291A, C1594T, G787A, G994A, and G1010C. The polymorphism at nt 1705 was in linkage disequilibrium with the A and C polymorphism, which indicated a multi-centric origin of the mutation. Further study of the promoter region and intron/exon boundary is under investigation.
