Objectives. Excessive acetabular coverage is the most common cause of pincer-type
femoroacetabular impingement. To date, an association between acetabular
over-coverage and genetic variations has not been studied. In this
study we investigated the association between single nucleotide
polymorphisms (SNPs) of paralogous Homeobox (HOX)9 genes and acetabular
coverage in Japanese individuals to identify a possible genetic
variation associated with acetabular over-coverage. . Methods. We investigated 19 total SNPs in the four HOX9 paralogs, then
focused in detail on seven of those located in the 3’ untranslated
region of HOXB9 (rs8844, rs3826541, rs3826540,
rs7405887, rs2303485, rs2303486, rs79931349) using a case-control
association study. The seven HOXB9 SNPs were genotyped
in 316 subjects who had all undergone radiological examination.
The association study was performed by both single-locus and haplotype-based
analyses. . Results. The genotype and allele frequencies of the five HOXB9 SNPs
showed significant association with acetabular over-coverage compared
with controls (rs7405887 OR = 3.16, p = 5.29E-6, 95% CI 1.91 to
5.25). A significant difference was also detected when haplotypes
were evaluated (OR = 2.59, p = 2.61E-5, 95% CI 1.65 to 4.08). The
two HOXB9 SNPs (rs2303485, rs2303486) were associated
with decreased acetabular coverage (rs2303485 OR = 0.524, p = 0.0091,
95% CI 0.322 to 0.855; rs2303486 OR = 0.519, p = 0.011, 95% CI 0.312
to 0.865). . Conclusions. The five HOXB9 SNPs (rs8844, rs3826541, rs3826540,
rs7405887, rs79931349) were associated with acetabular over-coverage.
On the other hand, the two SNPs (rs2303485 and rs2303486) were associated
with the lower acetabular coverage. The association of rs2303486
would be consistent with the previous study. Therefore, the HOXB9 SNPs might
be involved in the morphogenesis of acetabular coverage, and could
be an independent risk factor for developing pincer-type femoroacetabular
impingement. Cite this article: Bone Joint Res 2015;4:50–5
