No linkage to obesity in candidate regions of chromosome 2 and 10 in a selected sample of Swedish twins.
The aim of the current study was to investigate the importance of genetic and environmental effects in the variation of body mass index, and to investigate linkage for obesity to previously reported candidate regions on chromosome 2 and 10. A sample of 1422 twin pairs from the population based Swedish Twin Registry was used in order to estimate the genetic and environmental effects in the variation of body mass index by means of structural equation modeling. A selection of those, 51 concordant and 155 discordant for obesity, was used for the linkage analysis by implementing the "combined" Haseman-Elston approach. Heritability of body mass index ranged from 59-70%, implying that genetic effects were of importance for the variation of obesity, and there were significant sex and age differences. Linkage could not be verified in candidate regions of chromosomes 2 and 10, indicating that these genetic variants have a significant effect in extreme obese populations rather than in moderately obese Caucasians. However, the results were sensitive to issues related to power, minor effects of the genes, ethnic differences and the complex mechanism underlying obesity.
Department of Medical Epidemiology, Karolinska Institutet, Box 281, 171 77 Stockholm, Sweden. Anastasia.Iliadou@mep.ki.se
Anastasia
A
Iliadou
Paul
P
Lichtenstein
Susanne
S
Ahlberg
Johan
J
Hoffstedt
Peter
P
Arner
Martin
M
Schalling
Nancy L
NL
Pedersen
Catharina
C
Lavebratt
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D016009:Chi-Square Distribution; D002879:Chromosomes, Human, Pair 10; D002889:Chromosomes, Human, Pair 2; D004200:Diseases in Twins / Q000235:genetics*; D004777:Environment; D005260:Female; D008040:Genetic Linkage; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology / Q000235:genetics*; D010641:Phenotype; D012042:Registries; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology