Linkage of body mass index to chromosome 20 in Utah pedigrees.

Several linkage studies have hinted at the existence of an obesity predisposition locus on chromosome 20, but none of these studies has produced conclusive results. Therefore, we analyzed 48 genetic markers on chromosome 20 for linkage to severe obesity (BMI> or =35) in 103 extended Utah pedigrees (1,711 individuals), all of which had strong aggregation of severe obesity. A simple dominant model produced a maximum multipoint heterogeneity LOD score of 3.5 at D20S438 (55.1 cM). Two additional analyses were performed. First, a one-gene, two-mutation model (with one dominant mutation and one recessive mutation) increased the LOD score to 4.2. Second, a two-locus model (with one locus dominant and one recessive) generated a multipoint LOD score of 4.9. We conclude that one or more severe obesity predisposing genes lie within an interval of approx. 10 cM on chromosome 20. This study generated significant LOD scores which confirm suggestive linkage reports from previous studies. In addition, our analyses suggest that the predisposing gene(s) is localized very near the chromosome 20 centromere.

Functional status and emotional well-being, dietary intake, and physical activity of severely obese subjects.

OBJECTIVE: Analyze functional status and emotional well-being, energy and nutrient intake, and physical activity in sibling pairs raised together in the same family. DESIGN: One sibling classified as severely obese (body mass index > or = 35) and the other sibling as normal weight (body mass index < or = 27). SUBJECTS: From January 1994 through December 1996 at the Cardiovascular Genetics Research Clinic of the University of Utah School of Medicine, 145 sibling pairs (n = 290) were selected from a population-based, family history database or a hospital-based, very-low-energy weight-loss program. STATISTICAL ANALYSIS PERFORMED: Repeated-measures analysis of variance tested for differences between severely obese and normal-weight siblings. RESULTS: All functional status and emotional well-being scores (poorer perceived health) were significantly lower in severely obese siblings compared with normal-weight siblings. The severely obese siblings had a higher percentage dietary fat intake (3% higher) and total energy intake (more than 350 kcal higher), and lower weight-adjusted total energy intake (almost 10 kcal/kg lower) and activity energy expenditure (3.5 kcal/kg lower), compared with normal-weight siblings. Thus, environmental influences such as energy and nutrient intake and physical activity are highly related to severe obesity. APPLICATIONS: Previously shared environment of severely obese and normal-weight siblings raises questions about whether strong environmental influences or genetic predisposition account for the differences in sibling weight. When counseling individuals or families with a history of severe obesity, dietetics practitioners should be familiar with the potential for strong genetic factors and related environmental influences. In addition, dietitians should be prepared to offer a flexible approach to physical exercise as well as provide additional behavioral support.

The natural history of idiopathic chest pain in children. A follow-up study.

Repetitive chest pain of obscure origin is commonly encountered in older children and adolescents. A questionnaire study was conducted to determine the long-term outcome in 31 patients diagnosed as having idiopathic recurrent chest pain after an average 4.1-year follow-up period. Although 45 percent reported having had persistent symptoms, chest pain had disappeared in 81 percent of those followed more than 3 years. Equally reassuring is the fact that in no case did occult disease subsequently appear to account for the initial symptoms. This study supports the current clinical approach of limited diagnostic evaluation and reassurance in the management of these patients.