Genetic copy number variants implicated in childhood obesity
MedWire News: A US study has identified several genetic variations linked with obesity in children.
The researchers say the study represents the first large-scale, genome-wide scan of copy number variations (CNVs) for common pediatric obesity, which comprise an excess or absence of copies of a particular gene.
The team genotyped 550,000 single nucleotide polymorphism markers in 1080 European American obese children in the top fifth percentile of body mass index (BMI).
The study excluded the most obese children who were more than three standard deviations away from Centers for Disease Control and Prevention corrected BMI, due to the possible co-existence of other, confounding medical conditions.
The results were compared with 2500 lean children who were within the fiftieth percentile of BMI and positive findings further tested in 1479 African-American children who were obese and 1575 who were lean.
The team identified 17 CNV loci that were unique to at least three of the European-American children and had not previously been reported.
Eight of these loci (47.1%) were also found exclusively in the African-American children. These consisted of six replicated deletion loci that included EDIL3, S1PR5, FOXP2, TBCA, ABCB5 and ZPLD1 and two replicated duplication loci that were KIF2B and ARL15.
There was also evidence of a deletion at the EPHA6-UNQ6114 locus when the African-American children were investigated separately, report Hakon Hakonarson (The Children's Hospital of Philadelphia, Pennsylvania) and colleagues.
Reporting in the American Journal of Human Genetics, they acknowledge that the rare variants may not contribute greatly to the overall "missing heritability" in obesity.
Nonetheless, the team adds that the variants do present potentially novel biology underlying childhood obesity and notes: "To the individuals impacted by these variants they are very relevant to their disorder."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Anita Wilkinson