The Genetic Distance between the Coagulation Factor IX Gene and the Locus for the Fragile X Syndrome: Clinical Implications

In 3 families with the fragile-X [fra(X)] syndrome, we have identified a minimum of 4 recombinations in 9 meioses between the syndrome locus and the coagulation Factor IX gene. Two Factor IX intragenic restriction fragment length polymorphisms (RFLPs), produced with TaqI and XmnI, were used as markers. In lod score calculations, incomplete penetrance of the fra(X) mutation in males and females was taken into account by the computer program …