A complete deficiency of coagulation factor XIII A-subunit due to a novel compound heterozygote of Ser 413 Leu missense and an nt 389 (ins G) frameshift mutation

Coagulation factor XIII consists of two A- and two B-subunits, and either g ene mutation can cause a complete deficiency. In a newborn patient with per sistent bleeding from the umbilical cord stump, the plasma A-subunit protei n was not detectable. Direct PCR sequencing revealed an nt 389 (ins G) fram eshift mutation in exon 4 resulting in a new stop codon and a Ser 413 Leu m issense mutation in exon 10 in either allele. His mother and father were he terozygous for the nt 389 (ins G) and the Ser 413 Leu, respectively, with a bout 50% reduction of the plasma A-subunit proteins. In all family members examined only those with either mutation showed the reduced subunit A prote in levels,Thus, this complete deficiency of factor XIII was due to a novel compound heterozygous mutation in the A-subunit gene.