The reference OMIM entry for this protein is 262890

Scott syndrome; scts
Bleeding disorder, platelet-type, 7; bdplt7
Bleeding abnormality due to deficiency of platelet binding of factor x
Prothrombin conversion defect, familial
Prothrombin consumption deficiency
Prothrombin consumption inhib

A number sign (#) is used with this entry because Scott syndrome (SCTS) can be caused by homozygous mutation in the TMEM16F gene on chromosome 12q12 (608663).

DESCRIPTION

Scott syndrome is a mild platelet-type bleeding disorder characterized by impaired surface exposure of procoagulant phosphatidylserine (PS) on platelets and other blood cells, following activation with Ca(2+)-elevating agents (Munnix et al., 2003).

CLINICAL FEATURES

In 4 generations of a family (with 1 instance of male-to-male transmission), Robinson et al. (1967) described a mild bleeding disorder with no spontaneous hemorrhage. Analysis of blood coagulation in 2 generations revealed normal values for all clotting factors and other hemostatic systems except prothrombin consumption and thromboplastin inactivation. Robinson et al. (1967) demonstrated the presence of what they termed an 'inactivator' of active factor X (F10; 613872) in the plasma of these patients which accelerated the decay of blood thromboplastin. The inhibitor resembled that commonly observed in systemic lupus erythematosus; a similar agent was found in normal plasma but in much smaller amounts. Parry et al. (1980) studied 10 individuals from 3 unrelated Welsh families who had reduced prothrombin conversion as shown by a grossly abnormal prothrombin consumption index (PCI). Male-to-male transmission was reported. All known plasma coagulation factors were present in adequate concentrations; some affected persons had mild postoperative or postpartum bleeding but none suffered spontaneous bleeding. In therapeutic trials both plasma and platelet transfusions were needed to correct the abnormality. This finding, together with in vitro and other in vivo studies, suggested to Parry et al. (1980) that the abnormality was associated with an inhibitor of the interaction between plasma and phospholipid during blood coagulation. Parry et al. (1980) considered the abnormality similar but not identical to that in several members of the family reported by Robinson et al. (1967). Weiss (1994) reviewed the disorder of platelet coagulant activity known as Scott syndrome. Kojima et al. (1994) demonstrated that the coagulant nonresponder phenotype observed in platelets and erythrocytes in Scott syndrome is expressed by all of the EBV-transformed lymphoblasts derived from the B cells of the patient, and that the unique phenotype of the defective cells can be isolated by single cell cloning and propagated in culture through many generations. The continuous expression of the aberrant phenotype through in vitro culture confirmed that the Scott syndrome defect represents a gene deletion or mutation that is passed to daughter cells through mitosis. Furthermore, they demonstrated by heterokaryon hybridoma fusion that the abnormal Scott phenotype can be corrected by fusion with a cell exhibiting the normal coagulant-responder phenotype, and that the normal phenotype is sustained when these hybridomas are subsequently propagated through many generations. Taken together with the results of previous studies, these data suggested that the cellular defect in Scott syndrome reflects a mutation or deletion of a gene required for normal Ca(2+)-dependent transbilayer migration of phosphatidylserine to the plasma membrane surface and that this defect is shared among the blood cells of lymphoid, megakaryocytic, and erythroid lineages. Toti et al. (1996) characterized a familial instance of Scott syndrome and confirmed ... More on the omim web site

Subscribe to this protein entry history

May 12, 2019: Protein entry updated
Automatic update: OMIM entry 262890 was added.

Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).