Heterogeneity of oral clefts in relation to associated congenital anomalies

The first step in the search for the genetic basis of oral clefts should be the well-accepted classification and clinical data protocols, which are important in distinguishing separate phenotypic groups. The aim of this study was to compare the frequency of congenital malformations associated with oral clefts between the different groups of oral clefts.

The study population comprised 238 patients with oral clefts and one or more major congenital anomalies. All cases of oral clefts were subdivided into 2 groups: patients with the recognized conditions (n=97, 40.8%) and patients with the multiple congenital anomalies of unknown origin (n=141, 59.2%). The frequency of associated congenital anomalies was compared between the cleft palate (CP) and cleft lip and/or palate (CL/P) groups as well as between the cleft lip only (CL) and cleft lip with cleft palate (CLP) subgroups.

A total of 420 anomalies associated with oral clefts were diagnosed in 141 patients with multiple congenital anomalies (2.98 anomalies per proband) with the highest incidence being in the CP group (3.5 anomalies per proband). Comparison of the CP and CL/P groups showed that some of associated congenital anomalies such as atresia and stenosis of the small intestine and micrognathia occurred significantly more often in the CP than CL/P group (2.1% vs. 0% and 3.5% vs. 1.1%; P<0.05). Meanwhile, comparison of the CL and CLP subgroups revealed accessory auricle, other specified anomalies of the ear, congenital anomalies of the circulatory system, and certain congenital musculoskeletal deformities of the spine to be more common in the CL than CLP group (5.1% and 0.5%, 11.9% and 5.1%, 3.4% and 0%, 3.4% and 0%, respectively; P<0.05).

The highest incidence of associated congenital anomalies was in the CP group followed by the CL, CL/P, and CLP groups. Generally, the anomalies of the musculoskeletal system, cardiovascular system, and face including eye, ear, and neck were most common. The careful analysis of associated anomalies and cases of oral cleft subgroups with multiple congenital anomalies is helpful in identifying the etiologic entities and underscores the need for thorough evaluation and competent distinction of various types of oral clefts.