High heritability of fingertip arch patterns in twin-pairs

The presence of an arch pattern on at least one fingertip has previously been suggested as an autosomal dominant trait with reduced penetrance, although the examination of pedigrees with this trait segregating is also consistent with major gene or multifactorial inheritance. We utilized fingerprints in 2,484 twin-pairs to estimate heritability for the presence of at least one fingertip arch pattern. The frequency of arches in the entire sample was 4.3% (2,175/50,850), 5.5% in females and 3.2% in males. There were 267 twin-pairs concordant for the presence of an arch on any finger. Structural equation modeling was performed to contingency table data for five groups (MZ male, MZ female, DZ male, DZ female, and unlike-sexed DZ). The best fitting model, which allowed for the prevalence of arches to differ between males and females, had a heritability of 91%. There was some evidence for small dominant genetic effects in females and shared environmental effects in males, although both were not significant. With such high heritability, the search for specific genes influencing the occurrence of fingertip arch patterns is justified.