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Adhikari et al. Understanding the genetic basis of human facial variation
DOI:10.1038/bonekey.2016.94
In this genome-wide association study (GWAS) involving samples from the CANDELA cohort of around 6000 Latin Americans, Adhikari et al. discovered significant associations between specific single nucleotide polymorphisms (SNPs) and several key facial traits.
SNPs within four genomic regions were linked to nasal characteristics; nose wing breadth, nose bridge breadth and columella inclination. The four regions, encoding the genes GLI3, DCHS2, RUNX2 and PAX1, are all known to impact on nose morphology. An additional SNP was discovered within a region that is thought to influence the extent of chin protrusion; this region contains the EDAR gene.
The authors conclude that all five regions underpin the normal variations apparent within human facial features within the study population. They hope that further work on the GWAS sample will help to home in on gene mutations that could contribute to abnormalities in facial bone development.
Editor’s comment: Rare mutations in several of the identified genes are known to play a role in skeletal conditions: RUNX2 causes cleidocranial dysplasia, which is characterized by chondrocyte proliferation/maturation defects; PAX1 causes autosomal recessive oto-facio-cervical syndrome and GLI3 is associated with several Mendelian disorders that result in craniofacial and limb abnormalities. The authors also suggest that EDAR, a receptor related to the TNFα family, could play a role in craniofacial morphogenesis.
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