Homozygous 2bp deletion in the human factor VII gene: A non-lethal mutation that is associated with a complete absence of circulating factor VII

We report the case of a 5-year-old boy with severe factor VII deficiency. T he affected child presented at the age of 8 months and again at 18 months w ith bleeding from the gastrointestinal tract but the diagnosis of factor VI I deficiency was not made until the age of 3 years. He was treated with fre sh frozen plasma and subsequently factor VII concentrates and to date remai ns well. To identify the causative mutation, the factor VII gene was screen ed by SSCP and direct sequence analysis. A single homozygous 2bp deletion ( -CT) mutation was identified in exon la removing nucleotides 27/28 (codons 52/53). Both parents, who were first cousins, were heterozygous for the mut ation. The mutation located in the prepropeptide of factor VII, results in a complete absence of factor VII in plasma. This case indicates that a comp lete absence of plasma factor VII is not necessarily a lethal condition.