Fetal insulin-like growth factor (IGF)-I, IGF-II, and ghrelin in association with birth weight and postnatal growth in monozygotic twins with discordant growth.
OBJECTIVE
To investigate the relative contribution of genetic (fetal) vs. environmental (maternal/placental) factors on growth, we studied monozygotic twins with intertwin birth weight difference.


METHODS
Twenty-seven twins (15 with discordant growth) who have been treated for severe twin-to-twin transfusion syndrome by laser coagulation were studied. Cord blood samples were analyzed for IGF-I, IGF-II, IGF-binding protein-2, and ghrelin. Intertwin difference (Delta) of birth weight was correlated to Delta of the parameters analyzed. The Delta weight after 1 yr was correlated with Delta birth weight and all hormones.


RESULTS
The Delta birth weight was positively correlated with Delta IGF-I (r = 0.66; P < 0.0002) and negatively correlated with Delta IGF-binding protein-2 levels (r = -0.68; P < 0.001) but with neither Delta IGF-II nor Delta ghrelin. There was a strong intertwin correlation for all hormones. By comparing the growth in the first year, we found an overall reduction of the relative weight difference between the twins of 57%. ANOVA was used to calculate factors for prediction of postnatal catch-up growth. Besides the birth weight difference (R2= 0.84; P < 0.0001), only ghrelin was of prognostic value for postnatal catch-up growth (R2= 0.94; P = 0.0035).


CONCLUSIONS
These data confirm the importance of IGF-I in contrast to IGF-II for fetal weight. Additionally, ghrelin seems to be involved in fetal and probably postnatal growth.
Gohlke
Bettina C
BC
Department of Pediatrics, Zentrum für Kinderheilkunde, der Universität Bonn, Adenauerallee 119, 53113 Bonn, Germany. gohlke-bonn@t-online.de
Huber
Agnes
A
Hecher
Kurt
K
Fimmers
Rolf
R
Bartmann
Peter
P
Roth
Christian L
CL
D001724:Birth Weight; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D054439:Ghrelin; D006128:Growth; D006801:Humans; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007335:Insulin-Like Growth Factor II / Q000032:analysis*; D008137:Longitudinal Studies; D036361:Peptide Hormones / Q000097:blood*; D011247:Pregnancy; D014430:Twins, Monozygotic
D054439:Ghrelin; D018971:Insulin-Like Growth Factor Binding Protein 2; D036361:Peptide Hormones; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II