The arginine-552-cysteine (R1315C) mutation within the A1 loop of von Willebrand factor induces an abnormal folding with a loss of function resulting in type 2A–like phenotype of von Willebrand disease: study of 10 patients and mutated recombinant von Willebrand factor

Abstract

The study identified 10 patients from 6 families with prolonged bleeding time, decreased von Willebrand factor (vWF) ristocetin cofactor activity (RCoF) to vWF:Ag (antigen) ratio, and reduced ristocetin-induced platelet agglutination as well as ristocetin- or botrocetin-induced binding of plasma vWF to platelet glycoprotein Ib (GpIb). In addition, all patients showed a decrease of intermediate-molecular-weight (intermediate-MW) and high-molecular-weight (HMW) multimers of vWF. In the heterozygous state, a cysteine-to-threonine (C --> T) transversion was detected at nucleotide 4193 of the VWF gene of all patients and lead to the arginine (R)522C substitution in the A1 loop of vWF mature subunit (R1315C in the preprovWF). By in vitro mutagenesis of full-length complementary DNA (cDNA) of vWF and transient expression in COS-7 cells, the mutated C552 recombinant vWF (C552rvWF) was found to exhibit decreased expression, abnormal folding, and lack of intermediate-MW and HMW multimers. In addition, direct binding of botrocetin to C552rvWF, as well as ristocetin- and botrocetin-induced binding of C552rvWF to GpIb, was markedly decreased. Although being localized in an area of the A1 loop of vWF where most of the type 2B mutations that induce a gain-of-function have been identified, the R552C mutation induces a 2A-like phenotype with a decrease of intermediate-MW and HMW multimers as well as a loss-of-function of vWF in the presence of either ristocetin or botrocetin. (Blood. 2001;97:952-959)

Expanded phenotype–genotype correlations in a pediatric population with type 1 von Willebrand disease

“…The Vicenza mutation, which has been extensively studied and described elsewhere, was common within our cohort (17% vs. 6% in larger studies), and was consistently associated with a high PP/Ag ratio. The R1315C mutation is less well studied, and has been variably classified as type 1, type 2A, type 2M or ÔunclassifiableÕ in other reports [2,4,20,21]. In our cohort, we observed a reduced VWF:RCo/VWF:Ag ratio in most individuals with this mutation, possibly suggesting a reduction in VWF-dependent platelet adhesion; however, other observations suggest that the pathogenesis of the R1315C mutation may be more complex.…”

Evaluation of a semi‐automated von Willebrand factor multimer assay, the Hydragel 5 von Willebrand multimer, by two European Centers

“…Ten patients with p.R1205H (Vicenza VWD) were classified as type 1 VWD in this study although this mutation has also been classified as type 2M VWD 20. Three patients with p.R1315C were classified as type 2M but this mutation has also been linked with type 2A VWD 19, 21, 22. Eleven individuals, from four families, had p.R1374C/H, associated with both type 2A19 and 2M23 VWD.…”

Association of a missense mutation in the bovine leptin gene with carcass fat content and leptin mRNA levels

“…On substitution of the arginine for serine instead of cysteine, binding capacity and function returned to wild-type levels indicating the importance of the cysteine sulfhydryl group. Ribba et al [25] showed that the Arg552Cys mutation in the von Willebrand factor resulted in abnormal folding and loss of function resulting in type 2A-like phenotype of von Willebrand disease. The Arg615Cys substitution in ryanodine receptors increases calcium release in malignant hyperthermia-susceptible pigs [9].…”