Reduced prevalence of obesity in children with primary fructose malabsorption: a multicentre, retrospective cohort study.

BACKGROUND: Studies in animals and in man have demonstrated that excessive consumption of fructose can cause all components of the metabolic syndrome. OBJECTIVE: To investigate the impact of a condition resulting in decreased absorption of fructose, on obesity. METHODS: In a multicentre study, we analyzed a cohort of paediatric patients with suspected primary fructose malabsorption (FM). Patients with chronic intestinal diseases were excluded. The final cohort comprised 628 patients. RESULTS: 302 patients were diagnosed with primary FM (48.1%). The proportion of obese patients was lower among FM patients, compared to non-FM patients (2.3 vs. 6.1%, P = 0.029). Logistic regression analysis with inclusion of various covariates showed that FM was negatively associated with obesity (OR 0.35, 95% CI [0.13; 0.97]). We discuss several mechanisms involving the metabolic, endocrine and gastrointestinal system. CONCLUSIONS: Our data indicate that primary FM is negatively associated with childhood obesity.

Mapping of a first locus for autosomal dominant myxomatous mitral-valve prolapse to chromosome 16p11.2-p12.1.

Myxomatous mitral-valve prolapse (MMVP), also called Barlow disease, is a common cardiac abnormality and affects up to 5% of the population. It is characterized by an excess of tissue that leads to billowing of the mitral leaflets, sometimes complicated by prolapse. Typical histological findings include myxomatous degeneration and degradation of collagen and elastin. Previous reports have proposed an autosomal dominant inheritance of the trait, with age- and sex-dependent expression. By systematic echocardiographic screening of the first-degree relatives of 17 patients who underwent mitral-valve repair, we have identified four pedigrees showing such an inheritance. Genomewide linkage analysis of the most informative pedigree (24 individuals, three generations) showed a significant linkage for markers mapping to chromosome 16p, with a two-point maximum LOD score for D16S3068 (Zmax=3.30 at straight theta=0). Linkage to D16S3068 was confirmed in a second family (Zmax=2.02 at straight theta=0) but was excluded for the two remaining families, thus demonstrating the genetic heterogeneity of the disease. Multipoint linkage analysis performed, with nine additional markers, on the two families with linkage gave maximum multipoint LOD scores of 5.45 and 5.68 for D16S3133, according to a conservative and a stringent model, respectively. Haplotype analysis defined a 5-cM minimal MMVP-1 locus between D16S3068 (16p11.2) and D16S420 (16p12. 1) and a 34-cM maximal interval between D16S404 and D16S3068 when recombination events were taken into account only in affected individuals. The identification of this locus represents a first step toward a new molecular classification of mitral-valve prolapse.