SPINK1 and pachyonychia congenita: The area requires further research, because even large scale meta-analyses provide conflicting results in that area showing modest increase (OR, 1.41; 95% CI, 1.07–1.84; P = 0.013) in the risk of PC in CFTR mutation carries, whereas no association between PC and SPINK1 mutations (OR, 1.52; 95% CI, 0.67–3.45; P = 0.315) [48].