Leptin level and structure in Italian obese children

Abstract

Serum leptin levels and the relationship between leptin, gender, and anthropometric measurements were assessed in a group of 40 obese and 33 lean Italian children. The coding region of OB gene was screened by polymerase chain reaction (PCR) and single strand conformational polymorphism (SSCP) for mutations in 30 unrelated obese subjects. Mean fasting leptin level was significantly higher in the obese than in the control group (18.2 ±2.1 vs 7.1 ± 1.0 ng/ml; p<0.0005). No significant gender difference in leptin levels was observed in either obese or non obese subjects. Serum leptin levels were significantly correlated with BMI (p < 0.001), arm fat mass (p<0.001), triceps and subscapular skinfolds (p<0.005), and waist and hip circunferences (p<0.005). In males, leptin levels correlated significately with BMI and arm fat mass alone. No correlation was present between leptin levels and waist-hip ratio (WHR) in the whole population and in males and females separately. Fragments produced by amplification of OB gene exonic sequences demonstrated unique migration patterns after electrophoresis. This finding suggests the absence of mutations in the OB gene coding region in all patients. Elevated serum levels of normally structured leptin in a group of obese children suggest that they are insensitive to their endogenous leptin production. Analysis of the leptin receptor and of the signaling pathways triggered by the receptor will represent, consequently, next step toward identification of obesity molecular basis.