Fingernail angle in girls with Ullrich-Turner syndrome

Increased angle of insertion of the fingernails is known to be a common finding in girls with Ullrich-Turner syndrome (UTS), but there are few data on the frequency of this finding and no quantitative data that define what is a normal fingernail angle. To assess the usefulness of this measurement in evaluating patients with suspected UTS, we obtained tracings of 6 different fingernails to determine the mean fingernail angle (MFA) in 40 patients with UTS and compared the results with control girls and adults. As a group, the 24 girls with 45,X had an average MFA of 8.9 degrees, compared to 6.8 degrees for the 16 mosaics and variants, 3.0 degrees for normal children and 1.3 degrees for normal adults. Although there was overlap between the groups, 79% of 45,X girls and 56% of variants had an MFA of > 6 degrees, whereas only 8% of the combined control individuals had an MFA of > 6 degrees. Reproducibility of MFA determinations based on tracings obtained at consecutive visits was excellent (r = 0.92). There was no clear correlation between the MFA and the severity of the UTS phenotype. Determination of MFA is a simple, objective measurement which, when combined with other clinical findings, may aid the clinician in making a diagnosis of UTS.