The genes coding for A alpha-, B beta-, and gamma-chains of fibrinogen map to 4q2.

We used cloned cDNA probes for the A alpha-, B beta-, and gamma-chains of human fibrinogen and Southern blotting techniques to analyze DNA from a series of rodent X human somatic cell hybrids for the presence of specific fibrinogen-related sequences. Our results provide evidence for the assignment of the three genes for fibrinogen to chromosome 4. Moreover, by direct gene-dosage determination in two patients with chromosome 4 unbalanced rearrangements, we refined the regional chromosomal assignment to 4q2, thus suggesting that these three genes whose expression is coordinately regulated are closely linked.