CURRENT CLINICAL INTERESTS
Disorders of hemostasis including VWD, hemophilia, and platelet disorders.
Modifiers and genetics of von Willebrand Factor (VWF), von Willebrand Disease (VWD), hemophilia, and blood group antigens.
Dr. Johnsen's research focuses on the study of hereditary and acquired modifiers of blood traits, with particular emphasis on the genetics and biology of von Willebrand factor (VWF), von Willebrand Disease (VWD), hemophilia A and B, and blood group antigens with relevance to vascular disorders, blood coagulation phenotypes, and transfusion medicine.
Active projects include work in characterizing blood group gene diversity in minority populations using BloodSeq, a custom next generation DNA sequencing platform for predicting high resolution blood group antigen profiles; development of a silicon photonics multiplexed biosensor for small volume parallelized blood group antigen and anti-blood group antibody detection; genotyping patients and analyzing data in a nationwide collaborative project in hemophilia A and B patients and carriers; analysis of data related to hemophilia and hematology traits in Trans-Omics for Precision Medicine (TOPMed), an NIH NHLBI initiative to perform and whole genome sequencing coupled with other -omics and phenotype data for sharing and discovery; study of pregnancy-provoked changes in VWF; study of carbohydrate blood group antigens as modifiers of Factor VIII and VWF.
Fox K, Johnsen JM, Coe B, Frazar C, Reiner A, NHLBI Exome Sequencing Project, Minority Health-GRID Network, Eichler EE, Nickerson DA. Analysis of exome sequencing datasets reveals structural variation in the coding region of ABO in individuals of African ancestry. Accepted July 2016, Transfusion.
Johnsen JM. Using Red Blood Cell Genomics in Transfusion Medicine. Hematology American Society of Hematology Education Program. 2015 Dec 5;2015(1):168-76. PMID: 26637717
Byrnes JR, Duval C, Wang Y, Hansen CE, Ahn B, Mooberry MJ, Clark M, Johnsen JM, Lord ST, Lam W, Meijers JCM, Ni H, AriŽns RAS, Wolberg AS. Factor XIIIa crosslinking of fibrin a-chains mediates red blood cell retention in clots. Blood. 2015 Oct 15;126(16):1940-8. PMID: 26324704
Delaney M, Samantha H, Haile A, Johnsen J, Teramura G, Nelson K. Red blood cell antigen genotype analysis for 9,087 Asian, Asian-American and Native American blood donors. Transfusion. 2015 Oct;55(10):2369-75. PMID:26018321
Drury-Stewart DN, Lannert KW, Chung DW, Teramura GT, Zimring JC, Konkle BA, Gammill HS, Johnsen JM. Complex Changes in von Willebrand Factor (VWF)-Associated Parameters are Acquired During Uncomplicated Pregnancy. PLoS One. 2014 Nov 19;9(11):e112935. PMID: 25409031
Johnsen JM, Nickerson DA, Reiner AP. Massively parallel sequencing: the new frontier of hematologic genomics. Blood. Nov 7;122(19):3268-75, 2013. PMID:2402166
Johnsen JM, Auer PL, Morrison AC, Jiao S, Wei P, Haessler J, Fox K, Carlson CS, Smith N, Boerwinkle E, Kooperberg C, Nickerson D, Rich SS, Green D, Peters U, Cushman M, Reiner AP; NHLBI Exome Sequencing Project. Common and rare von Willebrand Factor (VWF) coding variants, VWF levels, and Factor VIII levels in African Americans: the NHLBI Exome Sequencing Project. Blood. Jul 25;122(4):590-7, 2013. PMID:23690449