A single nucleotide A>G polymorphism at position -670 in the Fas gene promoter: relationship to preterm premature rupture of fetal membranes in multifetal pregnancies.

OBJECTIVE

The relationship between a polymorphism at position -670 in the Fas gene (TNFRSF6) and preterm premature rupture of membranes (PPROM) in multifetal pregnancies was examined.

METHODS

Buccal swabs from 119 mother-infant sets were analyzed for an adenine (A) to guanine (G) substitution at position -670 in the TNFRSF6 promoter. Pregnancy outcome data were subsequently obtained. Analysis was by Fisher exact test.

RESULTS

Maternal allele G homozygosity (TNFRSF6G) was observed in 42.4% of 33 PPROM pregnancies as opposed to 19.5% of 77 with no spontaneous preterm birth (P = .01). Similarly, TNFRSF6G homozygosity was present in 37.5% of 32 first-born neonates from PPROM pregnancies as opposed to 18.7% of 75 uncomplicated pregnancies (P = .04). PPROM occurred in 8 of 14 (57.1%) pregnancies in which mother and all neonates were TNFRSF6G homozygotes as opposed to 25 of 105 (23.8%) cases in which uniform TNFRSF6G homozygosity was not observed (P = .02).

CONCLUSIONS

A genetic variant in the Fas gene is associated with an increased rate of PPROM in multifetal pregnancies.