Human chorionic gonadotrophin-β gene sequences in women with disorders of HCG production

Women with recurrent abortion, primary unexplained infertility, and gestational trophoblastic neoplasia (GTN) manifest disordered human chorionic gonadotrophin (HCG) secretion. Mutations in the HCGβ/luteinizing hormone (LH)β gene complex could cause aberrant HCG production in these disorders. The purpose of this study was to determine whether HCGβ gene deletions occur in women with recurrent abortion or primary unexplained infertility, and whether HCGβ gene duplications are present in women with GTN. DNA was extracted from 10 patients with unexplained recurrent abortion, 10 patients with unexplained primary infertility, 12 patients with GTN, three partners of women with GTN, and 30 controls. Southern blots were constructed and hybridized with DNA probes for HCGβ-5 and the LHβ gene. No gene deletions were identified in patients with recurrent abortion or primary unexplained infertility. Likewise, no gene duplications were identified in women with GTN. A previously described Mbol restriction fragment length polymorphism (RFLP) was identified in both patients and controls. A new Pstl RFLP was also characterized, but was present in patients and controls. Deletion/duplication mutations in the HCGβ/LHβ gene complex do not appear to be common causes of aberrant HCG production in humans with these disorders.