Lack of association of birth size with polymorphisms of two imprinted genes, IGF2R and GRB10.
Little is known about the determinants of birth size variability among individuals. Maternal and nutritional factors have been studied, but familial clustering suggests genetic factors as well. As a first step in testing this hypothesis, we examined common sequence variants in IGF2R and GRB10, two genes involved in the regulation of growth and subject to parental imprinting. The IGF2R gene was scanned with five polymorphisms spanning the coding and 3'-UTR for possible association with birth size in a set of 97 normal newborns in Greece. In addition, a silent SNP in GRB10 exon 2 was similarly tested as an exploratory first step. Birth weight and length were compared between groups of newborns divided according to which allele they had received from heterozygous parents. No significant differences were found between alleles in either gene, examined either by parental origin or in aggregate. Thus, we found no evidence that IGF2R variants modulate intrauterine growth within the normal range. If such variants exist in GRB10, they are not in linkage disequilibrium with the marker studied.
Kukuvitis
A
A
Department of Pedriatics, McGill University, Montréal, Canada.
Georgiou
I
I
Syrrou
M
M
Andronikou
S
S
Dickerman
Z
Z
Islam
A
A
McCann
J
J
Polychronakos
C
C
D000483:Alleles; D001483:Base Sequence; D001724:Birth Weight; D015331:Cohort Studies; D005260:Female; D005312:Fetal Blood; D005500:Follow-Up Studies; D051383:GRB10 Adaptor Protein; D005786:Gene Expression Regulation; D018392:Genomic Imprinting; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011506:Proteins / Q000235:genetics*; D017527:Receptor, IGF Type 2 / Q000235:genetics*; D047929:Term Birth
D011506:Proteins; D017527:Receptor, IGF Type 2; D051383:GRB10 Adaptor Protein