Intrauterine death: an approach to the analysis of genetic heterogeneity

Star-crossed? The association of the 5-HTTLPR s allele with season of birth in a healthy female population, and possible consequences for temperament, depression and suicide

BACKGROUND

Birth season has well-known effects on neuropsychiatric disorders, and may also influence genotype distribution by possibly influencing chance of conception via parental idiosyncratic conception patterns or survival of foetuses or infants. The 5-HTTLPR is associated with phenomena including affective temperaments or suicide which are also associated with birth season. Our aim was to investigate the association of 5-HTTLPR genotype and birth season in a healthy female population.

METHODS

Birth date and 5-HTTLPR genotype was determined for 327 psychiatrically healthy women. The association between presence of s allele and time of birth was analysed using generalized linear models.

RESULTS

A significant association between s allele frequency and time of birth was detected. S allele carrier frequency was marginally significantly higher in July borns and significantly lower in autumn borns.

LIMITATIONS

We investigated an adult sample so genotype frequency data do not reflect birth frequencies. Our sample consisted exclusively of females.

CONCLUSIONS

There is no clear explanation for the observed association, although idiosyncratic parental conception patterns, the association of 5-HTTLPR with sudden infant/intrauterine death, or other s allele-mediated behaviours may play a role. Our results are strikingly parallel with earlier data reporting a higher risk of completed suicide in July borns, and higher scores of July borns and lower scores of autumn borns on certain affective temperament scales, both of which are also associated with the s allele of 5-HTTLPR. Thus our results may add to the growing body of evidence regarding the etiological background of affective disorders.

Genetics of recurrent miscarriage: challenges, current knowledge, future directions

Recurrent miscarriage (RM) occurs in 1-3% of couples aiming at childbirth. Due to multifactorial etiology the clinical diagnosis of RM varies. The design of genetic/"omics" studies to identify genes and biological mechanisms involved in pathogenesis of RM has challenges as there are several options in defining the study subjects (female patient and/or couple with miscarriages, fetus/placenta) and controls. An ideal study would attempt a trio-design focusing on both partners as well as pregnancies of the couple. Application of genetic association studies focusing on pre-selected candidate genes with potential pathological effect in RM show limitations. Polymorphisms in ∼100 genes have been investigated and association with RM is often inconclusive or negative. Also, implication of prognostic molecular diagnostic tests in clinical practice exhibits uncertainties. Future directions in investigating biomolecular risk factors for RM rely on integrating alternative approaches (SNPs, copy number variations, gene/protein expression, epigenetic regulation) in studies of single genes as well as whole-genome analysis. This would be enhanced by collaborative network between research centers and RM clinics.

Intrauterine development and MNSs blood groups in repeated spontaneous abortion

OBJECTIVES

To determine whether the maternal MNSs genotype has an effect on the birth weight and gestation duration of the live offspring of women with repeated primary spontaneous abortion (RSA).

METHODS

The study sample consisted of 239 healthy white women who had been delivered of a live infant, and 137 women with a history of primary RSA-54 of whom had recently been delivered of a live infant and 83 who had had a spontaneous abortion. Maternal MNSs phenotypes were determined by standard serological methods, and the results were analyzed for relationships between these phenotypes and the mothers' reproductive status and the infants' birth weight and gestational age. Analysis of variance, the chi(2)-test of independence, and the Mantel-Haenszel test for linear association were performed for data analysis.

RESULTS

Infants born to mothers with the Ss genotype showed significantly lower birth weight and gestational duration compared with the infants of mothers with other genotypes. Additionally, the MNSs haplotype was found to be associated with birth weight.

CONCLUSIONS

Previous studies have shown that the MNSs system influences the gestational age of aborted fetuses in cases of RSA. The present study supports the hypothesis that this genetic factor influences intrauterine growth and development in women experiencing RSA.