Abnormal Morphology of the Soft Palate: II. The Genetics of Cleft Uvula

Abstract

Cleft uvula was recently reported to be present in one of every 75 individuals examined in an adult Caucasian population of 9,701 individuals (9). This frequency of occurrence is approximately 30 times greater that that of the more severe, but apparently related defect: isolated cleft of the secondary palate (2, 5, 12). Nevertheless, despite the apparent similarity between these malformations, their etiologic and genetic relationships have not been clearly investigated. Moreover, since the frequency of occurrence of these two defects appears to differ markedly and, since it has been hypothesized that cleft uvula is a minor manifestation of severe cleft palate (1, 11), the need to compare these relationships becomes even more apparent. Therefore, this study was designed primarily to investigate the genetic pattern of the transmission of cleft uvula in order to compare this with the transmission of severe cleft palate. A secondary purpose of the in— vestigation was to determine the prevalence of severe cleft palate and other congenital anomalies in the families of cleft uvula probands (in— dividuals with cleft uvulae). Methods and Materials All probands demonstrating cleft uvula in a previous frequency study (9) were contacted for participation in this study. Fifty-four cleft uvula probands were selected. All of these probands who agreed to participate had at least one parent residing within 30rmiles of our facilities who was available for examination. Forty-one subjects had uvulae bifurcated up to one-fourth of the total length, eight subjects had uvulae bifurcated from one—fourth to three-fourths of the total length, and five showed bifur-cations of from three—fourths to the total length of the uvula. The families of these probands who were available for examination included 101 parents and 97 siblings.