Diagnosis of Heterozygous State for Bernard-Soulier Disease

Gönül Hicsönmez, MD, Fevzi Őzkaynak, MD, Division of Hematology, Department of Pediatrics, Hacettepe University, Ankara (Turkey) Bernard-Soulier disease (BSD) is an inherited bleeding disorder characterized by a prolonged bleeding time, with a normal or decreased number of unusually large platelets which fail to aggregate in response to ristocetin. This disease is generally transmitted as an autosomal recessive disorder, but it has also been shown that abnormal platelet morphology is transmitted as an autosomal dominant [1]. In heterozygous BSD patients, giant platelets are found in significantly lesser numbers than in homozygous BSD patients. Heterozygotes of BSD are asymptomatic. Although they have not been well studied, it has been proposed that heterozygous subjects can be identified by their giant platelets [1–3]. More recently, George et al. [2] described an abnormal platelet membrane glycoprotein I concentration in 3 heterozygotes from two families with BSD. In this study we investigated ristocetin-induced platelet aggregation (RIPA) in heterozygous BSD patients to see if it might be helpful for their identification. 12 members from six families of patients with BSD were investigated. 6 of them were mothers, 4 fathers, and 2 were brothers of our patients. Their ages ranged from 6 to 45 years. With the exception of case No. 4, there was a consanguinity between the parents of all our patients. Platelet aggregation studies were Table I. Ristocetin-induced platelet aggregation in heterozygous subjects with Bernard-Soulier disease Patients Case No. Date Ristocetin-induced aggregation (Tmax), %’ father mother brother