Correlations of sinus, conical elevation, median depression of the lower lip and types of oral clefts

The incidence of autosomal dominantly inherited Van der Woude's syndrome among Finnish patients with cleft lip and palate CL(P) and with isolated cleft palate (CP) is approximately 2.5%. The incidence of conical elevation of the lower lip (CE) is 39% in CP and 0.8% in CL(P) patients. A pathogenetic similarity of sinuses and CE's was noted. The following classification was used to study associations between sinuses and CE's: (1) sinus; bilateral, unilateral, atypical; (2) CE: bilateral, unilateral; (3) median depression of the lower lip (MD); (4) combined sinus and CE; (5) combined CE and MD. According to the classification developed, a group of 77 sinus patients and 156 CE and/or MD patients was classified in subgroups of CL(P), CP, Pierre Robin anomalad (PR) and non-cleft subjects. The findings were: the sinus was bilateral on 52%, unilateral in 34% and atypical in 14%; the CE without associated sinus was bilateral in all cases; the sinus was associated with CE in 77% of all sinus subjects. The highly increased incidence of the CE in the CP (92%) and in the CL(P) (61%) sinus groups compared to the incidences of CE in these groups in general (39% and 0.8%) shows a close relationship between these 2 disorders of the lower lip, but the similarity of the genetic etiology still remains unclear.