Amniotic fluid insulin-like growth factor binding protein 3 concentration as early indicator of fetal growth restriction.
OBJECTIVE
Insulin-like growth factor-I (IGF-I) is an important regulator of fetal growth and its bioavailability depends on insulin-like growth factor binding proteins (IGFBPs). Genes coding for IGF-I and IGFBP3 are polymorphic. We hypothesized that either amniotic fluid protein concentration at the beginning of the second trimester or genotype of one of these two genes could be predictive of abnormal fetal growth.


METHODS
Amniotic fluid samples (14-18 weeks of pregnancy) from 123 patients with appropriate for gestational age (AGA) fetuses, 39 patients with small for gestational age (SGA) fetuses and 34 patients with large for gestational age (LGA) were analyzed. Protein concentrations were evaluated by ELISA and gene polymorphisms by PCR.


RESULTS
Amniotic fluid IGFBP3 concentrations were significantly higher in SGA compared to AGA group (P=0.030), and this was even more significant when adjusted to gestational age at the time of amniocentesis and other covariates (ANCOVA analysis: P=0.009). Genotypic distribution of IGF-I variable number of tandem repeats (VNTR) polymorphism was significantly different in SGA compared to AGA group (P=0.029). 19CA/20CA genotype frequency was threefold decreased in SGA compared to AGA group and the risk of SGA occurrence of this genotype was decreased accordingly: OR=0.289, 95%CI=0.1-0.9, P=0.032. Genotype distribution of IGFBP3(A-202C) polymorphism was similar in all three groups.


CONCLUSIONS
High IGFBP3 concentrations in amniotic fluid at the beginning of the second trimester are associated with increased risks of SGA while 19CA/20CA genotype at IGF-I VNTR polymorphism is associated with reduced risks of SGA. Neither IGFBP3 concentrations, nor IGF-I/IGFBP3 polymorphisms are associated with modified risks of LGA.
Murisier-Petetin
Geraldine
G
Department of Gynecology, Obstetrics and Medical Genetics, CHUV Hospital, Lausanne, Switzerland.
Gremlich
Sandrine
S
Damnon
Francoise
F
Reymondin
Danielle
D
Hohlfeld
Patrick
P
Gerber
Stefan
S
D000328:Adult; D000653:Amniotic Fluid / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism*; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D018598:Minisatellite Repeats / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000378:metabolism*; D012307:Risk Factors
D015415:Biomarkers; C515497:IGFBP3 protein, human; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I