Introduction: Associations between FABP2 Ala54Thr polymorphism and increased fasting insulin concentration, fasting fatty acid oxidation and reduced glucose uptake have been identified in several populations. The aim of this study was to evaluate the association of Ala54 Thr polymorphism of the FABP2 gene with insulin sensitivity in pubertal girls born small for gestational age (SGA).
Results: The frequency of the Thr54 allele did not differ between AGA and SGA girls (0.52 vs 0.43). Girls born SGA positive for the Ala/Thr polymorphism were older at the beginning of puberty compared to girls born AGA with the Thr54 allele (p < 0.01). These girls had lower whole body insulin sensitivity index (WBISI) (4.1 +/- 1.7 vs 9.2+/-7.4, p < 0.05), higher leptin (17.3 +/- 5.9 vs 12.1 +/- 13.7, p < 0.02), insulin area under the curve (AUC) (64,272 +/- 9,209 vs 27,981 +/- 15,637, p < 0.001), proinsulin (17.3 +/- 5.4 vs 10.9 +/- 3.6, p < 0.01) and insulinogenic index (4.6 +/- 3.0 vs 2.9 +/- 5.9, p < 0.01). Conversely, girls born SGA positive for the Ala/Thr polymorphism were older at the beginning of puberty (ns) compared to girls born SGA positive for the Ala/Ala polymorphism. These girls had higher insulin AUC (64,272 +/- 9,209 vs 33,322 +/-7,533, p < 0.01), insulinogenic index (4.6 +/- 3.0 vs 2.5 +/- 3.6, p < 0.01) and lower WBISI (4.1 +/- 1.7 vs 6.3 +/- 1.8, p < 0.05).
Discussion: Our results suggest that the Thr54 variant of the FABP2 gene could be associated with a synergic effect in the SGA group regarding higher leptin levels (p < 0.05), lower insulin sensitivity by WBISI (p < 0.05) and higher insulin secretion determined by higher insulinogenic index (p < 0.01), insulin AUC (p < 0.01) and beta-cell stress measured by higher proinsulin (p < 0.05). Our data suggest an involvement of genetic factors in the insulin resistance associated with reduced fetal growth and strengthen the hypothesis that this association could be the consequence of interactions between detrimental factors during fetal life and genetic susceptibility.