Antithrombin III: summary of first database update.

Antithrombin III is the most important inhibitor of coagulation proteinases such as thrombin and factor Xa. Inherited deficiency of antithrombin III is a well recognised risk factor for the early development of venous thromboembolism. The gene for antithrombin III is located at chromosome 1q 23-25 and its structural organisation has been described. A database of mutations of the antithrombin III gene has been compiled and a recent update lists 184 entries. These entries are listed according to subtype of deficiency and to nucleotide sequence number. There are 68 reports of type I 'classical' and 116 reports of type II 'variant' deficiencies. This summary considers the entries in terms of the number of unique molecular events, the nature of the genetic defects and the role of CpG dinucleotides in deficiency. Sample listings of type I and II deficiency entries are provided.