The effect of maternal overfeeding on pre-implantation conceptus development was investigated by transferring day-seven embryos (i.e., immediately after blastocyst formation) between HE and control mares and assessing the expression of genes coding for various imprinted genes and DNMTs, glucose and amino acid transporters in the conceptus membranes at day 28 of gestation (i.e., late in the pre-implantation period). The gene discussed is SLC38A7; the disease is hereditary elliptocytosis.