Adverse Effects of Trichothiodystrophy DNA Repair and Transcription Gene Abnormalities on Human Fetal Development

Abstract

The effects of DNA repair and transcription genes in human prenatal life have never been studied. Trichothiodystrophy (TTD) is a rare (affected frequency of 10^-6^) recessive disorder caused by mutations in genes involved in the nucleotide excision repair (NER) pathway and in transcription. Based on our clinical observations, we conducted a genetic epidemiologic study to investigate gestational outcomes associated with TTD. We compared pregnancies resulting in TTD-affected offspring (N=24) with respect to abnormalities in their antenatal and neonatal periods to pregnancies resulting in their unaffected siblings (N=18), accounting for correlation, and to population reference values. Significantly higher incidence of several severe gestational complications was noted in TTD-affected pregnancies. Gestational complications were noted in nearly all pregnancies resulting in TTD-affected offspring with XPD and TTDN1, but not TTD-A, gene mutations. Abnormal placental development may explain the constellation of observed complications; therefore, we hypothesize that some TTD genes play an important role in normal placental and fetal development. We investigated this hypothesis by analyzing the expression patterns of TTD genes. Expression of TTDA was strongly negatively correlated (r=-0.7,P<0.0001) with gestational age, while XPD, XPB and TTDN1 were consistently expressed from 14 to 40 weeks gestation. *Conclusion:* Our results indicate an important role for XPD, XPB and TTDN1 gene products during normal human placental and fetal development.