Genome-wide meta-analysis identified novel variant associated with hallux valgus in Caucasians

BACKGROUND

Hallux valgus, one of the most common structural foot deformities, is highly heritable. However, previous efforts to elucidate the genetic underpinnings of hallux valgus through a genome-wide association study (GWAS) conducted in 4409 Caucasians did not identify genome-wide significant associations with hallux valgus in both gender-specific and sex-combined GWAS meta-analyses. In this analysis, we add newly available data and more densely imputed genotypes to identify novel genetic variants associated with hallux valgus.

METHODS

A total of 5925 individuals of European Ancestry were categorized into two groups: 'hallux valgus present' (n = 2314) or 'no deformity' (n = 3611) as determined by trained examiners or using the Manchester grading scale. Genotyping was performed using commercially available arrays followed by imputation to the Haplotype Reference Consortium (HRC) reference panel version 1.1. We conducted both sex-specific and sex-combined association analyses using logistic regression and generalized estimating equations as appropriate in each cohort. Results were then combined in a fixed-effects inverse-variance meta-analyses. Functional Mapping and Annotation web-based platform (FUMA) was used for positional mapping, gene and gene-set analyses.

RESULTS

We identified a novel locus in the intronic region of CLCA2 on chromosome 1, rs55807512 (OR = 0.48, p = 2.96E-09), an expression quantitative trait locus for COL24A1, a member of the collagen gene family.

CONCLUSION

In this report of the largest GWAS of hallux valgus to date, we identified a novel genome-wide significant locus for hallux valgus. Additional replication and functional follow-up will be needed to determine the functional role of this locus in hallux valgus biology.

Factors associated with hallux valgus in a population-based study of older women and men: the MOBILIZE Boston Study

OBJECTIVE

To examine potential risk factors for hallux valgus in community-dwelling elders.

METHOD

Data from 600 MOBILIZE Boston Study participants (386 women and 214 men) were analyzed. Hallux valgus was defined as >15 degrees angular deviation of the hallux with respect to the first metatarsal bone toward the lesser toes. Associations of hallux valgus with age, body mass index (BMI), race, education, pes planus, foot pain, and in women, history of high heel shoe use, were assessed using sex-specific Poisson regression with robust variance estimation for risk ratios (RR) and 95% confidence intervals (CI).

RESULTS

Hallux valgus was present in 58% of women and 25% of men. Higher BMI was inversely associated with presence of hallux valgus in women (P trend=0.001), with the strongest inverse association observed in those with BMI of 30.0 or more compared to those with normal BMI (RR=0.7, 95% CI: 0.5, 0.9). Women, who usually wore high-heeled shoes during ages 20-64 years compared to those who did not, had increased likelihood of hallux valgus (RR=1.2, 95% CI: 1.0, 1.5). Among men, those with BMI between 25.0 and 29.9 had increased likelihood of hallux valgus compared to those with normal BMI (RR=1.9, 95% CI: 1.0, 3.5). Men with pes planus were more likely to have hallux valgus (RR=2.1, 95% CI: 1.3, 3.3) compared to men without pes planus.

CONCLUSION

In women, hallux valgus was associated with lower BMI and high heel use during ages 20-64, while in men, associations were observed with higher BMI and pes planus. Our results suggest that the etiologic mechanisms for hallux valgus may differ between men and women.