Dysregulation of alternative splicing of coagulation factor V results in bleeding disorder, east Texas type and other disorders of hemostasis

The studies completed herein explore different phenotypes related to the genetic defects that predispose individuals to a disruption of normal hemostasis. In the first study, a novel autosomal dominant bleeding disorder, which is characterized by excessive bleeding with trauma or surgery and menorrhagia in affected women, was studied in a large family (16 affected individuals) from east Texas. Affected members had a prolongation of their PT and/or aPTT, but normal clinical coagulation studies. Previous linkage analysis by Kuang et. al. (2001) mapped the defective gene to 1g23-24 (LODmax 7.22), which contains the gene for coagulation factor V (FV). I identified an alteration (A2440G) in the FV gene in exon 13 that segregated with the disease and was not present in 62 controls. Interestingly, this alteration resulted in a 22-fold up-regulation of a novel alternative splicing variant in patients' RNA versus controls. This translated into a similar fold increase in a 250-kDa isoform of FV seen in patients' plasma versus controls. A recombinant of this splicing event exhibited an increased sensitivity to cleavage by activated protein C (APC) that was more striking in the presence of PS. In addition, this novel isoform had increased APC cofactor activity, thus increasing the degradation of FVIIIa. These data indicated that A2440G up-regulates an alternatively spliced transcript of FV, and increases a FV isoform that hinders coagulation as opposed to promoting it like its wild-type counterpart. ^ The second study reports the largest screening to date of African Americans in two independent cohorts for a rare prothrombin variant, C20209T, which is suspected to be associated with thrombotic disease. The Texas Medical Center Genetics Resource (TexGen) Stroke DNA repository revealed 1.67% (Fisher p=0.27) of African American stroke patients were heterozygous for the 20209*T allele. Screening of the Atherosclerosis Risk in Communities Study (ARIC) cohort (n=3470) for the 20209*T allele revealed a population prevalence of 0.58% in individuals of African American descent; however, all associations with thrombotic disease were negative. Analysis of these two independent cohorts revealed that, unlike its neighbor G20210A, the C20209T variant does not increase the risk of thrombotic events in the African American population. ^

The Elegant Simplicity of Family Preservation Practice Legecies and Lessons

An earlier version of this manuscript was prepared for the Chapin Hall invitational seminar on family preservation, The Chapin Hall Center for Children at the University of Chicago, September 16 & 17, 1999. The author wishes to acknowledge the comments and helpful suggestions of seminar participants-Jacqueline McCroskey, Martha Shirk, Fran Jacobs, John Schuerman, Lee Schorr, Charlotte Booth, Kristi Nelson, Susan Kelly, Frank Farrow, and Susan Notkin. These comments, as indeed many of their prior contributions, have had a seminal effect on my thinking about family preservation services over the years. Clark Peters and other Chapin Hall staff deserve special thanks for creating the conditions necessary to produce a lively and productive discussion. As always, Harold Richman, Executive Director of Chapin Hall, and Hermon Dunlap, Smith Professor at the School of Social Service Administration of the University of Chicago, as seminar convenor combined perfectly the skills of gracious host and incisive critic. We in the child welfare field are in his debt for continually raising the level of discourse in our field. In the end, as it should be, the thoughts and opinions in the following paper are wholly my own.