Ghrelin gene polymorphisms and ghrelin, insulin, IGF-I, leptin and anthropometric data in children and adolescents.
BACKGROUND
Previous investigations on the ghrelin gene reported three common polymorphisms (Arg51Gln, Leu72Met, and Gln90Leu), but their role in overweight and obese individuals remains to be clarified.


OBJECTIVE
To ascertain whether these genetic variants could influence ghrelin secretion and play a part in predisposing to earlier onset of obesity or in modulating the overweight phenotype in childhood.


METHODS
Mutational analysis of the entire ghrelin gene and total and acylated plasma determinations were performed in 81 obese or overweight children and adolescents (46 were obese and 35 overweight: Ob/Ow). We also recruited 168 normal-weight healthy controls (72 young adults and 96 children) for mutational or plasma ghrelin analysis.


RESULTS
Median total and acylated plasma ghrelin concentrations were significantly lower in Ob/Ow individuals than in controls (175 pg/ml compared with 345 pg/ml, P<0.0001, and 95 pg/ml compared with 114 pg/ml, P<0.0001, respectively). The ghrelin gene variants showed similar allele frequencies in the Ob/Ow individuals and in controls; in the former, they were not associated with any change in total and acylated circulating ghrelin concentrations or anthropometric data. The Leu72Met status was associated with a positive family history for obesity (75% for Leu72Met compared with 39% for Leu72Leu, P=0.03) and with a greater percentage of newborns born 'large for gestational age' (33% for Leu72Met compared with 5% for Leu72Leu, P=0.03), but in the control group it was related to a lower mean body mass index z-score (-0.03 for Leu72Met and -0.47 for Leu72Leu, P=0.04).


CONCLUSIONS
Our present findings do not support the hypothesis that the ghrelin gene polymorphisms have a relevant impact in the secretion of total and acylated ghrelin.
Vivenza
D
D
Unit of Pediatrics, Department of Medical Sciences, University of Piemonte Orientale, 28100 Novara, Italy.
Rapa
A
A
Castellino
N
N
Bellone
S
S
Petri
A
A
Vacca
G
G
Aimaretti
G
G
Broglio
F
F
Bona
G
G
D000293:Adolescent; D000328:Adult; D001827:Body Height / Q000235:genetics; D001835:Body Weight / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D054439:Ghrelin; D006801:Humans; D007328:Insulin / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D020738:Leptin / Q000097:blood*; D008297:Male; D009765:Obesity / Q000235:genetics* / Q000378:metabolism; D036361:Peptide Hormones / Q000097:blood / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D011110:Polymorphism, Genetic
D054439:Ghrelin; D007328:Insulin; D020738:Leptin; D036361:Peptide Hormones; D007334:Insulin-Like Growth Factor I