Classification and birth prevalence of orofacial clefts

Abstract

To determine the proportion and birth prevalence of "typical" orofacial clefts (cleft lip (CL), cleft palate (CP), cleft lip and palate (CLP)) and "atypical" clefts (median, transversal, or oblique facial clefts) and the conditions in which they occur, we analyzed a population-based sample of 4,433 cases ascertained from 2,509,881 California births. We classified cases into: isolated cleft anomalies, sequences of the primary defect, chromosomal aberrations, monogenic syndromes, results of known teratogens, associations, multiple congenital anomaly (MCA) of unknown etiology, or conjoined twins. The birth prevalence of isolated CL+/-P was 0.77 per 1,000 births (CL 0.29/1,000, CLP 0.48/1,000) and of isolated CP, 0.31 per 1,000 births. Non-Hispanic Whites had the greatest prevalence of isolated clefts, Asians slightly lower prevalences, and Blacks the lowest. Asians had the lowest prevalence of Robin sequence and nonHispanic Whites the highest, twice that of Hispanics. Hispanics, followed by Asians, had the highest prevalence of CL+/-P with MCA; non-Hispanic Whites had the lowest. Asians had the lowest prevalence of CP; in Whites and Hispanics it was almost twice as high. Blacks had the highest CL:CLP ratio, followed by non-Hispanic Whites and Asians; Hispanics had the lowest. Isolated anomalies constituted 61.67% of clefts. In the total sample there were 3.9% sequences, 8.79% chromosomal aberrations, 6.02% monogenic syndromes, 0.2% known teratogens, 0.79% associations, 18.55% MCA of unknown etiology, and 0.1% in conjoined twins. This study supports evaluation of each child on a "case" level, and provides a framework for genetic counseling and other studies focused on causes and prevention of these serious anomalies.

Prenatal diagnostic rates and postnatal outcomes of fetal orofacial clefts in a Taiwanese population

“…Cleft palate with intact lip is the most difficult type of craniofacial malformation to diagnose prenatally; in this study, there were 10 fetuses with orofacial clefts that were not prenatally diagnosed, including 6 with cleft palate, 1 with cleft lip, 2 with unilateral CL/P, and 1 with bilateral CL/P. CL/P presents as an isolated finding or part of a complex of multiple congenital anomalies of unknown etiology [11]. The reported incidence of isolated cleft is 32%-58%, and the associated malformation rate is 42%-68% [1,4,5,12] (Table 4).…”

Epidemiology of cleft palate alone and cleft palate with accompanying defects

“…Use of the two sources gave an estimate of 31% of cases having accompanying defects, higher than most studies, but lower than others [9,10]. There was very little overlap in the two sources, indicating that accompanying defects were probably under-ascertained.…”

“…In most studies, the estimated occurrence of cleft palate with accompanying defects is 25% or less; [1][2][3][4][5][6] but other studies have reported 45% up to 70% [7][8][9][10] A few specific combinations of defects are known, such as the Pierre Robin Sequence, but most combinations are not recognized as specific syndromes [11]. Still, cases with multiple defects are often called ''syndromic'' cases.…”

“…Sayetta recommended classifying cases as familial or sporadic, then syndromic and non-syndromic within these categories [20]. Tolarova et al suggest dividing isolated cases from those with accompanying defects, and further dividing the accompanying defects into monogenic, chromosomal, known environmental, associations, and defects of unknown etiology [10]. Christensen simply recommends performing analyses of clefts with and without accompanying defects [17].…”

Cleft palate habilitation

“…1 Although cleft lip and palate are distinct and separate congenital abnormalities, they often occur concomitantly. 2 These deformities occur when mesenchymal connective tissues from different embryologic structures fail to meet and merge with each other.…”