Polymorphisms of the Nos3 gene and unexplained late intrauterine fetal death.
OBJECTIVE
Genetic polymorphisms associated with vascular diseases have been proposed to be involved in the pathogenesis of late unexplained intrauterine fetal death (IUFD). The Nos3 gene is known to regulate vascular tone via the endothelial nitric oxide synthase/nitric oxide pathway.


METHODS
In a multicenter case-control study, we evaluated two Nos3 polymorphisms (exon 7 Glu298Asp and a 27bp-repeat in intron 4) in 92 women with IUFD and 92 healthy control women.


RESULTS
The investigated Nos3 polymorphisms were not associated with the occurrence of IUFD. In the subgroup of pregnancies affected by IUFD, women with at least one mutant allele of the Nos3 intron 4 polymorphism were diagnosed with IUFD at a significantly earlier gestational age (31.8 [standard deviation (S.D.) = 4.9] weeks versus 34.6 [S.D. = 4.8] weeks, p = 0.02) and showed a significantly reduced birth weight (2113 g [S.D. = 1028] versus 1571 g [S.D. = 568], p = 0.03).


CONCLUSIONS
We are the first to report on Nos3 polymorphisms and IUFD. While not being associated with the incidence of IUFD overall, the intron 4 Nos3 polymorphism might modulate the timing of IUFD in affected pregnancies.
Huber
Ambros
A
Department of Obstetrics and Gynecology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
Grimm
Christoph
C
Jirecek
Stefan
S
Heim
Kurt
K
Zeillinger
Robert
R
Husslein
Peter
P
Hefler
Lukas
L
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005313:Fetal Death / Q000235:genetics*; D005838:Genotype; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D052250:Nitric Oxide Synthase Type III / Q000235:genetics*; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D044465:White People
C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III