A second case of prothrombin Puerto Rico I in the United States

Prothrombin deficiency is a very rare autosomal recessive bleeding disorder associated with mild to severe bleeding symptoms. We identified this bleeding disorder in a US-born patient as due to prothrombin Puerto Rico I. Unlike other prothrombin deficiencies, prothrombin Puerto Rico I is a series of concordant polymorphisms found in people of Puerto Rican descent with a much higher frequency than those prothrombin deficiencies found in the general population. This case underscores the importance of family history in identifying rare bleeding disorders.