Clinical Features, Genetics, and Management A Presenting Feature for Factor XIII Deficiency:

ABSTRACT. Objectives. The objectives of this studywere 1) to assess the importance of an early diagnosis forfactor XIII (FXIII) deficiency, and 2) to investigate themolecular basis and mechanism(s) of disease in the pa-tients under study. Methods. The case histories of 6 FXIII-deficient pa-tients were examined to assess the influence of earlyversus delayed diagnosis and replacement therapy. Thenucleotide sequence of the FXIIIA gene was determinedto identify the underlying mutations responsible for thebleeding diathesis in each patient. Molecular modelingwas used to predict the mechanism(s) of disease causa-tion for each mutation. Results. All cases presented with umbilical hemor-rhage. Patients 1 to 3 were diagnosed, and their prophy-lactic therapy was commenced in infancy. Diagnosis inpatients 4 to 6 was considerably delayed and, as a result,they continued to suffer from many bleeding symptoms.The FXIIIA gene mutations identified in these patientswere as follows: a homozygous G AA 3 A