Background: Ehlers-Danlos syndrome (EDS) is a heterogenous group of diseases that can be potentially life threatening in the vascular form. The diagnosis is mainly based on a clinical score including many items that demonstrate skin, mucosa, joint, and vessel involvement. The score is particularly helpful in hypermobile and classical forms but can be normal in the vascular type. The absence of the lingual and inferior labial frenula was reported to be a useful diagnostic tool in a series of 12 patients with classical and hypermobile EDS. However, two further reports have contested the value of this sign.
Objective: To determine the diagnostic value of the absence of inferior labial or lingual frenula in EDS.
Methods: Patients with EDS were prospectively recruited from November 2006 to April 2007 in a French tertiary center. Each patient was examined to check for the presence or absence of the oral frenula and matched with two controls seen from February to May 2007.
Results: Forty-three patients (ratio female/male of 2.07 : 1, mean age 31 years, range 4-63 years), 4 with classical EDS, 19 with hypermobile EDS, and 20 with vascular-type EDS, were included and matched with 86 controls. The sensitivity of the absence of the inferior labial frenulum was 42% (95% CI 27, 58) and for the lingual frenulum was 53.5% (95% CI 38, 69). The specificity was 99% (95% CI 94, 100) and 98% (95% CI 92, 100), respectively. In the vascular group, 13 of 20 patients were affected (sensitivity = 65% [95% CI 41, 85]; specificity = 97% [95% CI 87, 100]; odds ratio = 72 [95% CI 8, 645]). Inter-observer agreement was excellent (kappa value 0.91).
Conclusion: The absence of the inferior labial frenulum or lingual frenulum is a specific sign of EDS that can be easily checked by a physician. It can be helpful in the early diagnosis of the disease, including the vascular type, in affected families. It can also be helpful to distinguish between joint hypermobility syndrome and the hypermobile type of EDS in patients with joint hypermobility.