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P Raimondo

Publications and source records attributed to P Raimondo.

4 recordsLinked to original sources
PubMed2006

Weight loss in obese children carrying the proopiomelanocortin R236G variant.

To acquire more information relative to the course of obesity in conditions of food restriction in subjects carrying mutations in the melanocortin signaling pathway, 710 obese children (mean age: 9.5+/-2.1 yr; mean z-score body mass index: 3.63+/-1.6) were genotyped for the proopiomelanocortin (POMC) R236G substitution, a variant which has been associated to early onset obesity, by restriction fragment length polymorphism (RFLP) analysis. Three children were heterozygotes for the R236G variant (0.4%). One of them had the metabolic syndrome. This variant was not found in 400 controls. The 3 probands followed a hypocaloric balanced diet and, after about 12 months, normalized their weight as well as fat mass and insulin resistance. The patient with the metabolic syndrome reversed this condition. These results show that a) the R236G substitution of POMC gene, although not a major cause of obesity among Italian obese children and adolescents, is associated with early onset obesity, and that b) inherited alterations of the melanocortin signaling pathway, independently of the degree of obesity, do not preclude the possibility to lose weight in mutated individuals following a hypocaloric diet.

Adolescent↗
PubMed2004

Molecular screening of the ghrelin gene in Italian obese children: the Leu72Met variant is associated with an earlier onset of obesity.

OBJECTIVE: To test whether ghrelin variants could play a role in modulating some aspects of the obese phenotype during childhood. DESIGN: We screened the ghrelin gene in 300 Italian obese children and adolescents (mean age 10.5+/-3.2 y; range 4-19 y) and 200 controls by using the single-strand conformation polymorphism and the restriction fragment length polymoprhism analysis. RESULTS: No mutations were detected with the exception of two previously described polymorphisms, Arg51Gln and Leu72Met. For both variations, allelic frequencies were similar between patients and controls. Interestingly, we showed that the Leu72Met polymorphism was associated with differences in the age at obesity onset. Patients with the Met72 allele became obese earlier than homozygous patients for the wild Leu72 allele. The logrank test comparing the plots of the complement of Kaplan-Meier estimates between the two groups of patients was statistically significant (P<0.0001). CONCLUSION: It is unlikely that ghrelin variations cause the obesity due to single-gene mutations. The Leu72Met polymorphism of the ghrelin gene seems to play a role in anticipating the onset of obesity among children suggesting, therefore, that ghrelin may be involved in the pathophysiology of human adiposity.

Adolescent↗
PubMed2002

Low frequency of melanocortin-4 receptor (MC4R) mutations in a Mediterranean population with early-onset obesity.

BACKGROUND: Melanocortin-4 receptor (MC4R) mutations have been reported as the most common single genetic cause of obesity in some populations and it has been suggested that they may be responsible for more than 4% of early-onset obesity. OBJECTIVES: To verify the presence of mutations of the MC4R coding region in children from southern Italy with early-onset obesity. SUBJECTS AND METHODS: Two-hundred and eight unrelated obese children and adolescents were included in the study. The average age at obesity onset was 4.5+/-2.6 y. MC4R coding region was screened using both single-strand conformation polymorphism (SSCP) analysis and denaturing high-performance liquid chromatography (DHPLC). Automatic sequencing of PCR products of all individuals that showed an aberrant SSCP and/or DHPLC pattern was performed. RESULTS: One novel missense mutation and one previously described polymorphism (Vall03Ile) were identified. The missense mutation C142T, resulting in the substitution of proline with serine at codon 48, within the first MC4R transmembrane domain, was detected at the heterozygous state in a 15-y-old obese girl (body mass index (BMI)=35 kg/m(2)) who has been obese since she was 8 y old. The mutation co-segregated with the obesity phenotype for over three generations and was not found in the control population. CONCLUSIONS: Our data show MC4R obesity causing mutations in less than 0.5% of the patients (ie 1 out of 208 patients) and therefore indicate a low prevalence of MC4R variants in the obese population from southern Italy. The specific genetic background of the Mediterranean population could make it difficult for MC4R mutations to produce an essentially polygenic trait such as common obesity, at least during childhood.

Adolescent↗