Gene polymorphisms in leptin and its receptor and the response to growth hormone treatment in patients with idiopathic growth hormone deficiency

Abstract

This study aimed to investigate the relationships between genetic polymorphisms of leptin/receptor genes and clinical/biochemical characteristics in children with growth hormone deficiency (GHD). Ninety-three GHD children and 69 age-matched normal controls were enrolled. Anthropometric measurements, bone age, and laboratory test results were obtained. Polymorphisms in the LEP gene promoter locus (LEP-2548, rs7799039) and LEPR genes (K109R, rs1137100 and Q223R, rs1137101) were analyzed using PCR-RFLP. The serum leptin levels were measured using an ELISA kit. The median height and BMI z-scores of all GHD subjects were –2.20 and –0.26, respectively, and those of normal controls were –0.30 and –0.13, respectively. The serum leptin levels were similar between GHD subjects and normal controls (p = 0.537), but those were different between the complete GHD (6.97 ng/mL) and partial GHD (4.22 ng/mL) groups (p = 0.047). There were no differences in the genotypic distributions of LEP-2548, LEPR K109R, and Q223R between GHD subjects and normal controls. However, GHD subjects with the G allele at LEP-2548 showed higher IGF-1 (p = 0.047) and IGFBP-3 SDSs (p = 0.027) than GHD subjects with the A allele. GHD subjects with the G allele at LEPR Q223R showed lower stimulated GH levels (p = 0.023) and greater height gain after 1 year of GH treatment (p = 0.034) than GHD subjects with the A allele. In conclusion, leptin/leptin receptor genes are suggested to have the role of growth-related factors, which can affect various growth responses in children who share the same disease entity.