Novel mutation in the γ-glutamyl carboxylase gene resulting in congenital combined deficiency of all vitamin K-dependent blood coagulation factors

A mutation in the gamma -glutamyl carboxylase gene leading to a combined congenital deficiency of all vitamin K-dependent coagulation factors was identified in a Lebanese boy. He is the first offspring of consanguineous parents and was homozygous for a unique point mutation in exon 11, resulting in the conversion of a tryptophan codon (TGG) to a serine codon (TCG) at amino acid residue 501. Oral vitamin Kt administration resulted in resolution of the clinical symptoms. Screening of several family members on this mutation with an RFLP technique revealed 10 asymptomatic members who were heterozygous for the mutation, confirming the autosomal recessive pattern of inheritance of this disease. In 50 non-related normal subjects, the mutation was not found. This is the second time a missense mutation in the gamma -glutamyl carboxylase gene is described that has serious impact on normal hemostasis. (C) 2000 by The American Society of Hematology.