With regard to nutritional indicators, RBP concentrations were lower in the SFH <3rd centile compared with the >90th centile (P = 0.017) and protein deficiency (RBP <30 mg/L) was higher than expected in the SFH <3rd centile (P = 0.048); however, vitamin B-12 concentrations were higher in the SFH <3rd centile when compared with SFH 10–90 (P = 0.042). This evidence concerns the gene RBP4 and hereditary thrombophilia due to congenital protein S deficiency.