Red Blood Cell Stiffness Driving Patient Symptoms: A Study of Red Blood Cell Population Rigidity in Sickle Cell Patient Genotype SC Relation to Overlooked Clinical Symptoms

Sickle cell disease (SCD) is a systemic hematological disease. Various genotypes of the disease exist; however, the two most common include hemoglobin SS (Hgb SS) and hemoglobin SC (Hgb SC) disease. Hgb SC is typically considered a less severe genotype; however, some patients with SC disease still have significant complications. Ektacytometry is utilized to measure red blood cell deformability in sickle cell patients and may help identify patients at risk for severe disease. We described a patient with genotype hemoglobin SC with a more severe phenotype, who we show to have very rigid red blood cells via ektacytometry. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was in part supported by an NSF Research Grant (CBET1854726) to O.E.A. M.G. was supported by National Science Foundation Graduate Research Fellowship. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Blood draw protocols have been approved by the University of Michigan Internal Review Board (IRB-MED). SCD donors and legal guardians are informed of the study and give written consent before blood collection. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data generated or analyzed during this study are included in this published article and supplementary material. The raw datasets in this current study are available from the corresponding author on reasonable request. The identity of study participants will not be shared. * SCD : Sickle Cell Disease HgB : Hemoglobin RBC : Red Blood Cells MCHC : Mean Corpuscular Hemoglobin Concentration VOC : Vaso-Occlusive Crises PCA : Patient Controlled Analgesia EDL : Erythrocyte Diagnostic Laboratory IRB : Internal Review Board EDTA : Ethylenediaminetetraacetic Acid EI : Elongation Index