Investigation of common and rare genetic variation in the BAMBI genomic region in light of human obesity.
The aim of this study was to confirm the previously identified link between BAMBI and human obesity by means of a genetic and functional analysis. We performed both a mutation analysis, using high-resolution melting curve analysis, and a genetic association study, including 8 common tagSNPs in the BAMBI gene region. Three of the identified genetic variants (R151W, H201R, and C229R) were evaluated for their Wnt signaling enhancing capacity in a Wnt luciferase reporter assay. Mutation screening of the BAMBI coding region and exon-intron boundaries on our population of 677 obese children and adolescents and 529 lean control subjects resulted in the identification of 18 variants, 10 of which were not previously reported and 12 of which were exclusively found in obese individuals. The difference in variant frequency, not taking into account common polymorphisms, between obese (3.1 %) and lean (0.9 %) subjects was statistically significant (p = 0.004). Our Wnt luciferase assay, using WT and mutant BAMBI constructs, showed a significantly reduced activity for all of the investigated variants. Logistic and linear regression analysis on our Caucasian population of 1022 obese individuals and 606 lean controls, did not identify associations with obesity parameters (p values >0.05). We found several rare genetic variations, which represent the first naturally occurring missense variants of BAMBI in obese patients. Three variants (R151W, H201R, and C229R) were shown to reduce Wnt signaling enhancing capacity of BAMBI and we believe this result should encourage further study of this gene in other obese populations. In addition, we did not find evidence for the involvement of BAMBI common variation in human obesity in our population.
Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium.
Jasmijn K
JK
Van Camp
Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium.
Fenna
F
De Freitas
Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium.
Doreen
D
Zegers
Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium.
Sigri
S
Beckers
Department of Paediatrics, Antwerp University Hospital, Wilrijkstraat 10, 2650, Antwerp, Belgium.
Stijn L
SL
Verhulst
Department of Paediatrics, Antwerp University Hospital, Wilrijkstraat 10, 2650, Antwerp, Belgium.
Kim
K
Van Hoorenbeeck
Department of Paediatrics, Jessa Hospital, Stadsomvaart 11, 3500, Hasselt, Belgium.
Guy
G
Massa
Department of Endocrinology, Diabetology and Metabolic Diseases, Antwerp University Hospital, Wilrijkstraat 10, 2650, Antwerp, Belgium.
An
A
Verrijken
Department of Paediatrics, Antwerp University Hospital, Wilrijkstraat 10, 2650, Antwerp, Belgium.
Kristine N
KN
Desager
Department of Endocrinology, Diabetology and Metabolic Diseases, Antwerp University Hospital, Wilrijkstraat 10, 2650, Antwerp, Belgium.
Luc F
LF
Van Gaal
Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium. wim.vanhul@uantwerpen.be.
Wim
W
Van Hul
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D009765:Obesity / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D055815:Young Adult
C485671:BAMBI protein, human; D008565:Membrane Proteins
Bambi; Genetics; Human obesity; Wnt