Novel variants in Krueppel like factor 1 that cause persistence of fetal hemoglobin in In(Lu) individuals

Beta-hemoglobinopathies become prominent after birth due to a switch from γ-globin to the mutated β-globin. Haploinsufficiency for the erythroid specific indispensable transcription factor Krueppel-like factor 1 (KLF1) is associated with high persistence of fetal hemoglobin (HPFH). The In(Lu) phenotype, characterized by low to undetectable Lutheran blood group expression is caused by mutations within KLF1 gene. Here we screened a blood donor cohort of 55 Lutheran weak or negative donors for KLF1 variants and evaluated their effect on KLF1 target gene expression. To discriminate between weak and negative Lutheran expression, a flow cytometry (FCM) assay was developed to detect Lu antigen expression. The Lu(a−b−) (negative) donor group, showing a significant decreased CD44 (Indian blood group) expression, also showed increased HbF and HbA2 levels, with one individual expressing HbF as high as 5%. KLF1 exons and promoter sequencing revealed variants in 80% of the Lutheran negative donors. Thirteen different variants plus one high frequency SNP (c.304 T > C) were identified of which 6 were novel. In primary erythroblasts, knockdown of endogenous KLF1 resulted in decreased CD44, Lu and increased HbF expression, while KLF1 over-expressing cells were comparable to wild type (WT). In line with the pleiotropic effects of KLF1 during erythropoiesis, distinct KLF1 mutants expressed in erythroblasts display different abilities to rescue CD44 and Lu expression and/or to affect fetal (HbF) or adult (HbA) hemoglobin expression. With this study we identified novel KLF1 variants to be include into blood group typing analysis. In addition, we provide further insights into the regulation of genes by KLF1.

Novel variants in Krueppel Like Factor 1 that cause Persistence of Fetal Hemoglobin in In(Lu) individuals

Beta-hemoglobinopathies become prominent after birth due to a switch from γ-globin to the mutated β-globin. Haploinsufficiency for the erythroid specific indispensable transcription factor Krueppel-like factor 1 (KLF1) is associated with high persistence of fetal hemoglobin (HPFH). The In(Lu) phenotype, characterized by low to undetectable Lutheran blood group expression is caused by mutations within KLF1 gene. These KLF1 variants often lead to KLF1 haploinsufficiency. We screened a donor cohort of 55 Lutheran weak or negative donors for KLF1 variants. To discriminate between weak and negative Lutheran expression, a flow cytometry (FCM) assay was developed to detect Lu polymorphisms. The Lu(a-b-) (negative) donor group, showing a significant decreased CD44 (Indian blood group) expression, also showed increased HbF and HbA2 levels, with outliers expressing >5% HbF. KLF1 exons and promoter sequencing revealed variants in 80% of the Lutheran negative donors. Thirteen different variants plus one high frequency SNP (c.304T>C) were identified of which 6 were novel. In primary erythroblasts, knockdown of endogenous KLF1 resulted in decreased CD44, Lu and increased HbF expression, while KLF1 over-expressing cells were comparable to wild type (WT). In line with the pleiotropic effects of KLF1 during erythropoiesis, distinct KLF1 mutants expressed in erythroblasts display different abilities to rescue CD44 and Lu expression and/or to affect fetal (HbF) or adult (HbA) hemoglobin expression.

Racing Indian Language, Languaging an Indian Race

This chapter is an exploration of how race and language become entangled in representations and ideas about what it means to be seen and recognized as Native American. Most conceptions of Indianness derive from scholarly European-derived representations and evaluations and from popular narrative media, the one often bootstrapping the other. In tandem, these public manifestations perpetuate the racialization of Indian languages and of Indianness, most ubiquitously in and through a discourse of “blood.” Several ideologies configure the racial logic that determines Indianness: purism (percentage of “Indian blood”), visibility (racialized—and cultural—manifestations of “blood”), continuity (maintenance of a pre-contact “bloodline”), and primitivism (expression of indigenous “blood” in and through language). I argue that this “ideological assemblage” (Kroskrity 2018) undergirds the processes of “racing Indian language(s)” and “languaging an Indian race” (H. Samy Alim 2016) that has resulted in propagating conflicts over and denials of Native American heritage.