Hereditary factor VII deficiency is a rare autosomal and recessive disorder, and a variety of mutations have so far been identified in relation to the decreased level of the factor in plasma. A single point mutation of C to T in the codon(ACG) for Thr359 creating a codon (ATG) for Met has so far been identified in seven patients. This amino acid exchange is thought to be responsible for the impaired secretion of the protein, resulting in a severe deficiency of the factor in plasma. Although severe bleeding is a common symptom in six out of the seven patients, only mild bleeding was observed in another single patient. The patient we report here, a 69-year-old man, has also been identified to have the same type of C to T exchange causing the Thr359Met mutation associated with decreased levels of both factor VII coagulant acitivity (1.3%) and antigen (less than 1.0%). Nevertheless, the patient has recently manifested only a subtle bleeding tendency of petechiae that may not be ascribed to the deficiency of factor VII in his plasma. The asymptomatic manifestation observed in this patient appears to be distinct from the symptomatic clinical manifestations of severe bleeding in six patients and mild bleeding in a single patient with this type of mutation so far reported.

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