Evidence of decreased fertility in women carrying the gene for G6PD deficiency: a study in the Sardinian population

The current trend toward reduced feritility and delayed childbearing has stimulated an interest in the genetic and environmental factors capable of modifying fertility. The evaluation of fertility in GOD-deficient females is of great theoretical interest in view of the proposed heterozygote advantage of GOD deficiency in malarial environments. Toncheva and Tzoneva have reported population data from Bulgaria suggesting decreased fertility of women carrying the risk allele for G6PD deficiency. We have applied a model of maternal-age related differences within the distribution of 'fertility-types' among women, described by Gimelfarb and Bottini (1989) to a sample of 5182 Sardinian mothers. Mothers of infants with G6PD deficiency are underrepresented in the group of women having children at younger ages, suggesting a reduction of so-called 'natural fertility' among women carrying the risk allele for GOD deficiency. Female infants with G6PD deficiency from young mothers have a lower birth weight compared to infants without GOD deficiency from older mothers, suggesting that in younger mothers there is a negative effect of GOD deficiency on intrauterine growth.