Erythrocyte dehydration is a distinguishing feature of hematological diseases including sickle cell anemia and hereditary spherocytosis (HS). Identification of genes influencing hydration status will increase our understanding of red cell pathologies and provide new targets for risk assessment and drug development. We mapped quantitative trait loci (QTLs) influencing red cell hydration using the cell hemoglobin concentration mean (CHCM) as a marker of hydration status. CHCM (analogous to the calculated mean cell hemoglobin content, MCHC) was obtained using an Advia 120 whole blood analyzer, which provides a direct measure of hemoglobin concentration on a cell-by-cell basis. We established seven F2 intercrosses and one backcross and phenotyped 200–500 offspring from each cross at 8–10 weeks of age. Genome-wide scans were performed to detect single loci associated with CHCM (main effect QTL) using the R/qtl software (www.rqtl.org). Significance thresholds were determined by permutation testing (1000 permutations). A highly significant locus was identified on chromosome 7 in 6 of the 8 crosses (maximum LOD score of 82) with a 95% confidence interval (CI) spanning from approximately 90–129 mega base pairs (Mb). Previously we identified two QTL for CHCM (
Disclosures: No relevant conflicts of interest to declare.