Hypodontia in children with various types of clefts

The prevalence of hypodontia in children with clefts, both inside and outside the cleft region, and the possible association between the side of the cleft and the side of the missing teeth were studied using radiographs of 278 patients with cleft lip, cleft palate, or both (158 boys and 120 girls), age 5 to 18 years (mean age 10.4 years). A hypodontia prevalence of 77% (excluding third molars) was found for the total cleft sample. This was significantly higher, both statistically and clinically, than the incidence of hypodontia reported for noncleft populations, and considerably higher than the prevalence reported in other studies of children with clefts. The maxillary permanent lateral incisors were the teeth most frequently missing on the cleft side (259 teeth) followed by the maxillary (47 teeth) and mandibular (23 teeth) second premolars, in both boys and girls. The teeth that were most often missing on the noncleft side were the maxillary second premolars (12 teeth), followed by the maxillary lateral incisors (10 teeth) and mandibular second premolars (6 teeth). Hypodontia of both the maxillary lateral incisors and second premolars was found more frequently on the left side, which also has a higher frequency of clefting.     

A review of tooth formation in children with cleft lip/palate

The literature on tooth formation in children with cleft lip and/or palate is reviewed. The main focus of interest is the association of cleft type and dental abnormalities in number, size, shape, timing of formation, and eruption and cause of the abnormalities. The upper lateral incisor is the most susceptible to injury in the area of cleft in both deciduous and permanent dentitions. This tooth is affected in most instances, even in the cases of microforms of the cleft lip. The prevalence of hypodontia increases strongly with the severity of cleft. More teeth are congenitally missing from the upper jaw than from the lower jaw; however, in the permanent dentition both jaws are affected. Very high prevalence of hypodontia are observed in connection with the Van der Woude syndrome associated with cleft and with the Pierre Robin anomaly. Hypodontia is similarly prevalent in subjects with isolated cleft palate with and without a positive family history of clefts. The prevalence of hypodontia varies largely in different populations. Asymmetric formation of the contralateral teeth is a milder form of hypodontia. The prevalence of asymmetrically developing pairs of teeth is far more common in children with clefts than in children with normal palates or lips. In the permanent dentition the timing of tooth formation is delayed in children from all cleft groups compared to noncleft children. The delay lengthens (with increasing severity of cleft) from 0.3 to 0.7 years and is similar in all permanent teeth in both jaws. In children with hypodontia, the delay is still more severe. As the child becomes older, the delay may increase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Congenitally missing teeth in the Israeli cleft population.

OBJECTIVE: The purpose of the study was to determine the prevalence of congenitally missing teeth in a group of Israeli children with various types of clefts. DESIGN: Prevalence of congenitally missing teeth was determined for 179 children with cleft lip, cleft lip and alveolar ridge, cleft lip and palate, and cleft palate. Subgroupings were assessed according to patient sex, origin, cleft type, tooth type, and the side of hypodontia. The diagnosis of congenitally missing teeth (CMT) was based on initial and follow-up panoramic roentgenograms. In case of doubt, occlusal or periapical roentgenograms as well as clinical dental photographs were also used. SETTING: Data collection was conducted at the Rambam Medical Center, Orthodontic and Craniofacial Unit, Haifa, Israel. RESULTS: In the total cleft group, 67.6% of the patients presented with hypodontia, totaling 246 missing teeth. A statistically significant difference was found in the distribution of patients with CMT of Jewish and minority origin according to sex. Cleft lip and palate was the most frequently affected group in which 195 teeth were missing. The most frequently missing tooth among the cleft population was the maxillary incisor. The order of frequency of the other missing teeth was the same as in the normal population. Hypodontia and malformations of permanent teeth were most common on the cleft side. CONCLUSION: The frequency of CMT in the Israeli cleft population studied was higher than in the intact population. This confirms findings in other populations worldwide.     

Dental development of Chinese children with cleft lip and palate.

OBJECTIVE: To compare the dental development and rate of tooth development between children with and without cleft lip and palate. Patients: Age- and gender-matched pairs (231 in all) of southern Chinese children ages 3 to 12 years, with and without cleft lip and palate. METHODS: Dental histories and radiographs were studied. From these, dental development was determined. RESULTS: Of 2946 tooth pairs in the children with cleft lip and palate, 252 (8.6%) were found to be asymmetric, significantly (p < .001) more than the 63 of 3179 (2.0%) tooth pairs observed in the children without cleft lip and palate. The teeth with the highest frequency of asymmetry were the maxillary lateral incisors (38.1%). Differences in dental development on the cleft versus noncleft sides of children with unilateral cleft lip and palate were significant for both maxillary and mandibular teeth (p < .001 and p = .039, respectively). The mean delay in tooth formation of the children with cleft lip and palate was 4.4 months relative to the children without cleft lip and palate. The majority of the teeth in the cleft lip and palate group were delayed by one developmental stage. This happened in 40.0% of the maxillary teeth and 30.1% of the mandibular teeth. The delay in tooth formation increased as the number of missing teeth increased in the children with cleft lip and palate, although not significantly. CONCLUSIONS: This group of southern Chinese children with cleft lip and palate demonstrated a higher prevalence of asymmetric and delayed dental development than did their counterparts who did not have cleft lip and palate.     

An investigation of the dentition of parents of children with cleft lip and palate.

OBJECTIVE: The aim of this investigation was to identify whether any dental features in parents of children with cleft lip and palate can be useful as predictors of clefting. METHODS: The dentition of 28 pairs of parents of children with complete unilateral (17) and bilateral (11) cleft lip and palate and 21 pairs of parents of noncleft children were evaluated. Clinical and radiographic examinations were carried out to identify abnormalities of tooth number and morphology. Study cast assessment was undertaken to evaluate incisor relationship, overjet, overbite, intercanine widths, and mesiodistal widths of individual teeth, and these data were subjected to statistical analysis. RESULTS: The prevalence of abnormalities of tooth number in parents of cleft children was similar to those reported elsewhere for general populations. In parents of children with unilateral clefts, there was no tooth-size asymmetry between teeth on the side corresponding to the child's cleft and noncleft sides, respectively. No differences were found in tooth widths and intercanine widths between parents of children with unilateral clefts and parents of children with bilateral clefts. The incisor relationship, overjet, overbite, and intercanine widths were found not to differ statistically between the parents of cleft children and parents of noncleft children. CONCLUSIONS: No predictors of clefting could be identified in the dentition of parents of children with cleft lip and palate.     

Root development of permanent lateral incisor in cleft lip and palate children: a radiographic study.

OBJECTIVE: The objective of this study was to compare the root development of lateral incisor on the cleft side with the root development of its contralateral tooth in cleft lip and palate children. SETTING: Cleft lip and palate wing, Meenakshi Ammal Dental College and Hospital, Chennai, South India. MATERIALS AND METHODS: A sample of 96 orthopantamograms of patients with unilateral orbilateral cleft lip and/or cleft palate was selected, regardless of sex and race. MAIN OUTCOME MEASURE: Orthopantamograms were analyzed for root development of lateral incisor on the cleft and non cleft side. Associated anomalies like hypodontia, supernumerary teeth, malformed lateral incisors and root development of canine, if present, were recorded. FINDINGS AND CONCLUSIONS: Root development of permanent lateral incisor was delayed on the cleft side compared to the non cleft side. There was a statistically significant relationship between levels of root development of lateral incisors on the cleft side within the different study groups(P < 0.05). Incidence of hypodontia increased in proportion to cleft severity. Frequency of missing second premolars, supernumerary teeth and malformed lateral incisors increased in cleft lip and palate patients. Root development of canine showed a slight delay on the cleft side when compared to the canine on the noncleft side.     

Cranial base morphology in cleft lip and palate: a cephalometric study from 7 to 18 years of age.

Four cleft lip/palate groups were cephalometrically compared with a noncleft control group using three cranial base dimensions: anterior (ACB) and posterior (PCB) cranial base, and cranial base angle (CBa). The groups were compared by age from 7 to 18 years. The results showed that the cleft lip and/or alveolus group was not different from the control group in the three dimensions. Unilateral and bilateral cleft lip and palate and isolated cleft palate cases were generally shorter in ACB and PCB for most of the growth period, particularly after age 8 to 9 years. The cranial base angle remained similar for all the cleft groups when compared with the noncleft group. These findings support the view that intrinsic tissue defects or errors during embryologic development may result in basicranial abnormalities and orofacial clefting.     

非综合征性单侧完全性唇腭裂恒牙发育异常的研究

目的 经回顾性研究了解非综合征性单侧完全性唇腭裂患者恒牙发育异常的情况.方法 收集244例植骨期非综合征性单侧完全性唇腭裂患者的影像学资料,记录和统计分析恒牙发育异常.结果 在本研究中各种恒牙异常的发生率为:先天缺失163例(269颗)(163/244,66.8%),最常累及的牙位是上颌侧切牙;畸形牙82例(85颗)(82/244,33.6%),绝大多数为上颌侧切牙的小牙畸形;额外牙12例(12颗)(12/244,4.9%),多发生于裂区,表现为畸形小牙.牙位发育异常的性别比较发现,非裂侧上颌仅侧切牙缺失,男性高于女性(P<0.05).裂侧的先天缺牙、额外牙和畸形牙的发生率均高于非裂侧,差异有统计学意义(P<0.01),上下颌均有相同发现.结论 非综合征性单侧完全性唇腭裂患者各类牙齿发育异常的患病率均高于健康人群.裂侧的牙齿发育异常较非裂侧更为多见.

Abstract：

Objective To investigate the prevalence of dentM anomalies in Chinese children with complete unilateral cleft lip and palate(UCLP).Methods Dental histories and radiographs of 244 Chinese children with UCLP were collected.The diagnosis of dental anomalies waft based on panoramic radiographs before alveolar bone grafting.All patients were over 8 years old.Results In the UCLP group,66.8% of the patients was presented with hypodontia.The maxillary lateral incisors were the most common teeth affected,followed by maxillary second premolars,mandibular incisors and mandibulax second premolars.A total of 33.6%the patients Was presented with dental malformation,most were mierodontic laterel incisors.A total of 4.9% the patients was presented with hyperdontim The supernumerary teeth were more frequently found in the cleft region.The prevalence of missing maxillary lateral incisor in the noneleft side was statistically different between genders,which was higher in male(P<0.050).This group of Chinese children with UCLP demonstrated significantly higher prevalence of hypodontia,hyperdontia,and malformation on the cleft side than on the noncleft side(P<0.01).Conclusions Hypodontia is the most common type of dental anomalies.The prevalence of dental anomalies is higher in the UCLP patients than in the normal population.Dental anomalies occur more frequently on the cleft side than on the nonclefi side.     

MSX1 and orofacial clefting with and without tooth agenesis

MSX1 has been considered a strong candidate for orofacial clefting, based on mouse expression studies and knockout models, as well as association and linkage studies in humans. MSX1 mutations are also causal for hereditary tooth agenesis. We tested the hypothesis that individuals with orofacial clefting with or without tooth agenesis have MSX1 coding mutations by screening 33 individuals with cleft lip with or without cleft palate (CL/P) and 19 individuals with both orofacial clefting and tooth agenesis. Although no MSX1 coding mutations were identified, the known 101C > G variant occurred more often in subjects with both CL/P and tooth agenesis (p = 0.0008), while the *6C-T variant was found more often in CL/P subjects (p = 0.001). Coding mutations in MSX1 are not the cause of orofacial clefting with or without tooth agenesis in this study population. However, the significant association of MSX1 with both phenotypes implies that MSX1 regulatory elements may be mutated.     

Visual and statistical modeling of facial movement in patients with cleft lip and palate.

OBJECTIVE: To analyze and display facial movement data from noncleft subjects and from patients with cleft lip and palate by using a new dynamic approach. The hypothesis was that there are differences in facial movement between the patients with cleft lip and palate and the noncleft subjects. SETTING: Subjects were recruited from the University of North Carolina School of Dentistry Orthodontic and Craniofacial Clinics. PATIENTS, PARTICIPANTS: Sixteen patients with cleft lip and palate and eight noncleft "control" subjects. INTERVENTIONS: Video recordings and measurements in three dimensions of facial movement. MAIN OUTCOME MEASURES: Principal component (PC) scores for each of six animations or movements and dynamic modeling of mean animations. STATISTICS: Multivariate statistics were used to test for significant differences in the PC mean scores between the patient groups and the noncleft groups. RESULTS: No statistically significant differences were found in PC mean scores between the patient groups and the noncleft groups; however, the variability of the effect of clefting on the soft tissues during animation was noted when the noncleft data were used to establish a "normal" scale of movement. Compensatory movements were seen in some of the patients with cleft lip and palate, and the compensation was not unidirectional. CONCLUSION: Measures of mean movement differences as summarized by PC scores between patients with cleft lip and palate and noncleft subjects may be misleading because of extreme variations about the mean in the patient group that may neutralize group differences. It may be more appropriate to compare patients to a noncleft normal scale of movement.     

Dental age in children with a complete unilateral cleft lip and palate.

OBJECTIVE: To assess dental age in children with a complete unilateral cleft lip and palate and to compare this with a noncleft control group. DESIGN: Two-group, mixed-longitudinal cohort study. SETTING: Cleft group from an academic center for cleft lip and palate treatment. Noncleft control group from the same population. PATIENTS: Participants included 70 Caucasian children with a full complement of teeth and a complete unilateral cleft lip and palate (45 boys and 25 girls) from the Cleft Palate Craniofacial Center at the Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands. The control group (90 boys and 91 girls) was taken from the Nijmegen Growth Study. MAIN OUTCOME MEASURE: Dental age was assessed on orthopantomograms. In the unilateral cleft lip and palate group, linear interpolation in individual age curves was applied to obtain the dental age at 5, 9.5, and 14 years of age. For these ages, a comparison was made with the noncleft control group. RESULTS: Boys and girls with a unilateral cleft lip and palate showed a significant delay in dental age, as compared with their noncleft peers at all three ages. This delay was more pronounced in boys than in girls. The gender effect was significant at chronological ages 5 and 14 years. CONCLUSIONS: Children with a complete unilateral cleft lip and palate have a delay in dental age, compared with noncleft children.     

The prevalence of various dental characteristics in the primary and mixed dentition in patients born with non-syndromic unilateral cleft lip with or without cleft palate

This retrospective study was carried out on consecutively collected dental casts, x-rays, and photos of 129 Swedish children who had been born with non-syndromic unilateral (U) cleft lip (CL), cleft lip and alveolus (CLA), or cleft lip and palate (CLP). The following dental characteristics were investigated in the primary and permanent dentitions: 1. the presence, eruption, position, and shape of the lateral incisor; 2. the prevalence of rotation and enamel hypoplasia of the permanent central incisor; 3. the occurrence of hypodontia outside the cleft region; and 4. the transition from the primary to the succeeding permanent lateral incisor in the cleft region. Patients with clefts involving the palate (UCLP) exhibited a high frequency of hypodontia. In patients with clefts, which did not include the palate, malformed lateral incisors were a common finding. In the primary and permanent dentition, the lateral incisor had erupted distal to the cleft in 31.8 and 24.8 per cent of the UCLA and UCLP patients, respectively. No significant pattern was seen regarding the transition from the primary to the succeeding permanent lateral incisor (P = 0.15). The central incisor was rotated in 55 per cent of the patients and this positional deviation was particularly frequent in cases where the lateral incisor was missing in the premaxilla (P < 0.05). Hypodontia outside the cleft region was recorded in 15.5 per cent of the patients. Patients with UCLP had more often crossbite than patients with a UCL or a UCLA phenotype (P < 0.001).     

Left-sided predominance of hypodontia irrespective of cleft sidedness in a French population

Objective : Individuals with oral clefts exhibit considerably more dental anomalies than do individuals without clefts. Our aim was to evaluate the prevalence of tooth agenesis in a sample composed of 124 children (81 boys and 43 girls, mean age 12.5?years) with clefts registered with the Cleft Palate Center in Strasbourg (France). Design : Cleft types and dental agenesis were assessed by clinical and radiographic examination. Cleft types were divided into four groups according to the clinical extent of the cleft (cleft lip only [CL, 12.9%], cleft lip and alveolus [CLA, 4%], cleft lip and palate [CLP, 49.2%], and cleft palate only [CP, 33.9%]). Results : Of the subjects 63% had evidence of hypodontia: maxillary lateral incisors (54%) and upper and lower premolars (32%) were the most common missing teeth. The number of dental ageneses associated with CP (54%) and CLP (79%) was significantly higher than that with CL (33%). All these anomalies were found in proportionately higher frequencies as the severity of the cleft increased, and we found left side predominance for hypodontia (p < .01) irrespective of cleft sidedness. Conclusions : Both right-sided and left-sided clefts were more frequently correlated with left-sided dental agenesis. This left-sided prevalence suggests that common signaling malfunctions might be involved, both in dental development anomalies and cleft genesis.     

Hypodontia in twins discordant or concordant for cleft lip and/or palate

The aims of this study were to determine the frequency of hypodontia of permanent teeth in twins discordant or concordant for clefts in each type of cleft, to determine the concordance of hypodontia in mono- and dizygotic twins, and to compare the findings with some earlier data. Thirty-nine pairs of twins between 7 and 23 yr of age were investigated. Six of 13 monozygotic and 24/ 26 dizygotic pairs were discordant for clefts. Orthopantomograms of the dentition, treatment records, and anamnestic data were studied. Twenty-three pairs of twins (59%) had at least one twin with hypodontia: 9/13 (69%) monozygotic and 14/26 (54%) dizygotic. The prevalence of hypodontia was 37% for monozygotic and 32.7% for dizygotic twins, 16.7% in the noncleft and cleft lip groups, 41.1% in the cleft palate group, and 64.3% in the cleft lip and palate group. All these were above the values observed earlier in the noncleft twins and in the Finnish normal and cleft group populations. Four of 13 pairs of monozygotic twins had no hypodontia, 8/9 pairs were discordant, and only 1/9 was concordant for hypodontia. The corresponding figures for the 26 dizygotic pairs were: 12/26, 11/14, and 3/14 pairs. Maxillary second premolars were the most frequently absent teeth, followed in order of frequency by the maxillary lateral incisors and the mandibular second premolars. Hence, for this sample of twins, the genetic component seems to be weak.     

Oral disease status of a sample of Jordanian people ages 10 to 28 with cleft lip and palate.

OBJECTIVE: To determine the levels of periodontal disease and dental caries in subjects with cleft lip and palate and to compare them with matched noncleft control subjects. DESIGN: A total of 32 subjects with cleft lip and palate, ages 10 to 28 years, and a similar number of noncleft control subjects were examined for plaque biofilm deposits, gingivitis, periodontitis, and dental caries by using the Silness and L?e plaque index (PI), L?e and Silness gingival index (GI), probing pocket depth (PPD), and the decayed-missing-filled-teeth (DMFT) index, respectively. SETTING: Faculty of Dentistry, Jordan University of Science and Technology, and Prince Rashed Hospital, Royal Medical Services, northern Jordan. RESULTS: Scores for PI, GI, PPD, and DMFT were significantly higher in subjects with cleft lip and palate than in control subjects. CONCLUSION: Subjects with cleft lip and palate are at an increased risk for dental caries and periodontal disease when compared with a noncleft population.     

Correlations between microforms of the Van der Woude syndrome and cleft palate

The lower lip was examined in 397 children with isolated cleft palate (CP), in 518 cleft lip children with or without cleft palate (CL(P)) and in 1000 noncleft children. Familial occurrence of clefts, other concomitant anomalies and the type and extension of the cleft were determined from the child's medical history. A total of 323 orthopantomograms, taken at the ages of 6-12 years, were available in the detection of hypodontia of the permanent teeth excluding the third molars in the CP group. The incidence of lower lip sinus and microforms (conical elevations, CE) was noted. The incidence of sinuses was 2.3% in the CP group, 2.5% in the CL(P) group and 0% in the noncleft group. The corresponding figures for CE were 39.3%, 0.8% and 0.7%, respectively. In the CP group with CE, the familial occurrence of clefts was statistically higher (30.0%) than in the group without CE (20.7%). The corresponding figures for hypodontia were 40.7% and 24.7%, respectively. Conical elevations are cleft palate related disturbances in the development of the lower lip. At least in certain cases the CE do represent microforms of the sinus syndrome. Thus the question arises: do the CE always represent microforms of the Van der Woude syndrome, or are they only pathogenic similarities of a variable etiology?     

Comparison of three nonradiographic methods of mixed dentition analysis in cleft lip and palate patients.

PURPOSE: The purpose of this study was to investigate whether the application of mixed dentition analyses in cleft lip and palate patients differed from noncleft patients and to investigate which method provided the most accurate prediction in cleft lip and palate patients. METHODS: Study casts of 30 cleft lip and palate patients and 30 noncleft patients were used in this study. Each patient had dental casts at two stages of dental development. The methods compared included the Moyers, the Tanaka & Johnston (T/J) and the Boston University (BU) prediction methods. RESULTS: Analyses for both groups indicated that the predicted values yielded by each method were significantly different from one another but were all significantly correlated with actual tooth size. Moyers 50% and BU had the smallest mean difference values and no significant difference between the predicted and actual values for both cleft and noncleft control groups. CONCLUSIONS: Types of cleft had no effect on the size of the mandibular permanent canines and premolars. The application of mixed dentition analyses in cleft lip and palate patients does not differ from noncleft patients. Both Moyers 50% and the BU method have high accuracy and correlation in prediction of unerupted teeth in both groups.     

Is missing maxillary lateral incisor in complete cleft lip and palate a product of genetics or local environment

Objective:To test the null hypothesis: Subjects with isolated complete unilateral cleft lip and palate (UCLP) show no differences in overall frequency of tooth agenesis (hypodontia), comparing a subsample with cleft-side maxillary lateral incisor (MxI2) agenesis to a subsample without cleft-side MxI2 agenesis. Findings could clarify the origins of cleft-side MxI2 agenesis.Materials and Methods:Tooth agenesis was identified from dental radiographs of 141 subjects with UCLP. The UCLP cohort was segregated into four categories according to the status and location of MxI2 in the region of the unilateral cleft: group M: subjects with one tooth, located on the mesial side of the alveolar cleft; group D: subjects with one tooth, located on the distal side of the alveolar cleft; group MD: subjects with two teeth present, one mesial and one distal to the cleft; and group ABS: subjects with lateral incisor absent (agenesis) in the cleft area.Results:The null hypothesis was rejected. Among UCLP subjects, there was a twofold increase (P < .0008) in overall frequency of tooth agenesis outside the cleft region in a subsample with cleft-side MxI2 agenesis (ABS), compared to a subsample presenting with no agenesis of the cleft-side MxI2 (M+D+MD).Conclusions:Cleft-side MxI2 agenesis in CLP subjects appears to be largely a genetically controlled anomaly associated with cleft development, rather than a collateral environmental consequence of the adjacent cleft defect, since increased hypodontia involving multiple missing teeth observed remote from a cleft clearly has a significant genetic basis.     

Van der Woude syndrome: dentofacial features and implications for clinical practice

Background:  Van der Woude syndrome (VWS) is the most common clefting syndrome in humans. It is characterized by the association of congenital lower lip fistulae with cleft lip and/or cleft palate. VWS individuals have a high prevalence of hypodontia. Although caused by a single gene mutation, VWS has variable phenotypic expression. This study aimed to describe the range of clinical presentations in 22 individuals with VWS to facilitate its diagnosis.
Methods:  A retrospective study of 22 patients with a diagnosis of VWS was undertaken at the Australian Craniofacial Unit (ACFU) in Adelaide. Three extended families with affected members were included in the study cohort.
Results:  The overall prevalence of lip pits in this study cohort was 86%. Cleft phenotypes included bilateral cleft lip and palate (32%); unilateral cleft lip and palate (32%); submucous cleft palate (23%); and isolated cleft hard and soft palate (9%). Missing permanent teeth were reported in 86% of affected individuals.
Conclusions:  Submucous cleft palate in VWS may go undiagnosed if the lower lip pits are not detected. Associated hypodontia and resultant malocclusions will also require management by a dental team.     

Distribution of orofacial clefts and frequent occurrence of an unusual cleft variant in the Rift Valley of Kenya.

OBJECTIVE: To investigate the pattern and distribution of nonsyndromic orofacial clefts among patients in the Rift Valley region of northwestern Kenya. METHODS: Subjects were categorized anatomically for occurrence of an atypical cleft lip variant (ACL), typical cleft lip (CL), cleft lip and palate (CLP), or cleft palate (CP), and family history of orofacial clefts. Tribal ethnicity data were obtained from both cleft and noncleft clinic attendees. RESULTS: There were 194 patients with CL (52.7%), 153 with CLP (41.6%), and 21 with CP (5.7%). CL constitutes a greater fraction of orofacial clefts in the Rift Valley region than reported elsewhere in Africa, principally due to frequent occurrence of ACL (52.5% of all CL). Among noncleft clinic attendees there was a lower fraction of Bantu and larger fraction of Nilotic-Paranilotic tribal ethnicity than in Kenya overall. In contrast, among patients with orofacial clefts there was significant underrepresentation of Bantu and overrepresentation of Nilotic-Paranilotic tribes, particularly Kalenjin. Patients of Kalenjin origin had a much higher rate of positive family history of orofacial clefts than Bantu patients. CONCLUSIONS: There is an unusual anatomic distribution of orofacial clefts in the Kenya Rift Valley, with frequent occurrence of an atypical CL variant. Our findings indicate that Bantu tribes have lower risk of orofacial clefts than Nilotic-Paranilotic tribes, possibly due to inherited genetic differences, perhaps accounting for the relatively low prevalence of orofacial clefts through much of Africa.