Worldwide diffusion of FVII Arg304Gln coagulation defect (FVII Padua)*

Abstract

FVII Padua is a Type 2 defect owing to an Arg304Gln substitution in exon 8. The defect was originally discovered in an isolated valley in northeastern Italy. Subsequently, it was described in several other countries of the Mediterranean basin and Middle East. Recently, several proven or suspected cases have been described among Afro-Americans in the USA. This study has demonstrated the existence of at least a two-founder effect for this FVII abnormality, Mediterranean countries, and USA Afro-Americans. Patients are usually asymptomatic or only paucisymptomatic. The defect is characterized by low FVII activity when rabbit brain thromboplastins are used in the assay system. On the contrary, FVII levels are normal when ox-brain thromboplastins are used. FVII antigen is always normal.