Birthweight and fetal glycosylated hemoglobin at birth in newborns carrying the GLUT1 XbaI gene polymorphism.
BACKGROUND
Low birthweight is an independent risk factor of glucose intolerance and type 2 diabetes in later life. Genetically determined insulin resistance and subsequently impaired glucose uptake might explain both reduced fetal growth and elevated blood glucose. The glucose transporter 1 (GLUT1) plays an important role for fetal glucose uptake as well as for maternal-fetal glucose transfer, and it has been associated with insulin resistance in adults. The present study hypothesized that the common fetal GLUT1 XbaI polymorphism might reduce fetal insulin sensitivity and/or glucose supply in utero, thus affecting fetal blood glucose and fetal growth.


METHODS
A genetic association study was conducted at the obstetrics department of the Charité University Hospital, Berlin, Germany. 1191 white women were included after delivery, and all newborns were genotyped for the GLUT1 XbaI polymorphism. Total glycosylated hemoglobin was quantified, serving as a surrogate of glycemia during the last weeks of pregnancy.


RESULTS
The analysis of this large population showed no significant differences in fetal glycosylated hemoglobin or birthweight for the different fetal GLUT1 XbaI genotypes. Only newborns carrying the mutated allele show the previously published inverse association between birthweight and glycosylated hemoglobin.


CONCLUSIONS
The results suggest that there is no prenatal effect of the fetal GLUT1 XbaI polymorphism on fetal insulin sensitivity, intrauterine fetal glucose supply or fetal growth. However, the polymorphism seems to modulate the inverse interaction between birthweight and fetal glycemia.
Institute of Nutritional Science, University of Potsdam, Potsdam, Germany. hocher@uni-potsdam.de
Berthold
B
Hocher
Dirk
D
Heimerl
Torsten
T
Slowinski
Michael
M
Godes
Horst
H
Halle
Friedrich
F
Priem
Thiemo
T
Pfab
D000328:Adult; D001724:Birth Weight / Q000502:physiology*; D005260:Female; D051272:Glucose Transporter Type 1 / Q000235:genetics*; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D008297:Male; D036801:Parturition / Q000097:blood; D020641:Polymorphism, Single Nucleotide; D011247:Pregnancy / Q000097:blood
D051272:Glucose Transporter Type 1; D006442:Glycated Hemoglobin; C495677:SLC2A1 protein, human