October 24, 1977

Factor XI Deficiency-Reply

Author Affiliations

Yale University Health Services New Haven, Conn

JAMA. 1977;238(17):1811-1812. doi:10.1001/jama.1977.03280180015008

In Reply.—  Dr Soloway presents a number of pertinent questions and comments, certain of which were spoken to in the original editorially scrutinized manuscript, later contracted for publication. Answers to his specific questions are as follows: (1) 45 seconds; (2) kaolin; (3) no, specific factor analyses were performed, and only factor XI was below the generally accepted norms for the several factors; (4) no; and (5) no.In 1953, Rosenthal described a type of hemophilia owing to plasma thromboplastin antecedent deficiency (PTA), or hemophilia C.1 Following elucidation of this defect, other cases were reported in the literature. Two types of patients were defined. The first group was severely affected with multiple episodes of bleeding and hemorrhage; a second group was much less symptomatic, often only identifiable by clotting factor analysis. The severely affected group on clotting factor analysis was noted to have a factor XI level of 20% of