The oral health of children with clefts--a review

A Unique Appliance for Median Facial Cleft Management With Sleep Apnea due to Undeveloped Nasal Septum: A Rare Case Report

The role of a prosthodontist in the management of facial cleft patients is the restoration of feeding, respiration, facial harmony, dental harmony and phonation. This case report presents the fabrication of an appliance for a pediatric patient with congenital median facial cleft who had sleep apnea due to the absence of nasal septum, which is a rare condition, with a unique method that fulfilled the patient's needs and improved quality of life. The patient also had median cleft lip and premaxilla along with hypertelorism.

Evaluation of the Change in Halitosis with the Improvement in Oral Health in Cleft Lip and Palate Patients

AIM

This study aimed to assess the effects of hygiene education on periodontal health and mouth/nasal halitosis in patients with cleft.

MATERIALS AND METHODS

39 patients with cleft who were accepted for orthodontic treatment divided into two groups as with (Group1; n = 24) and without braces (Group2; n = 15). Plaque Index (PI), Gingival Index (GI), and Tongue coating Index (TCI) values were recorded. The BANA test microbiological kit, was used to determine the amount of anaerobic bacteria. Values of volatile sulfur components (VSC) for the measurement of oral and nasal halitosis were measured with a Halimeter device. After the initial measurements, oral hygiene instructions were given to eliminate the plaque production on teeth, periodontal structure, tongue and palate. All measurements were repeated 4 weeks after the hygiene instructions. Wilcoxon and Mann-Whitney U test were used for statistical analysis.

RESULTS

In both groups, the PI, GI, values were significantly decreased (P < .05). Tongue coating area, thickness and TCI were significantly reduced (P < .05). Oral halitosis values decreased significantly (P < .05). The PI values decreased significantly more in the Group 1 (P < .05). Non significant difference was detected in nasal halitosis in both groups. In unilateral cleft lip and palate cases cases (n = 23), no significant difference was found in nasal halitosis values between the cleft and the healthy sides (P > 0.05).

CONCLUSION

In patients with clet cases, periodontal health was improved and oral halitosis was reduced by the given hygiene education; brushing the teeth, especially the tongue and palate. However, hygiene education did not have a significant effect on nasal halitosis. Key Words: Cleft lip and palate, Halitosis, BANA test, Periodontal index.

Dental Caries Experience among Children and Adolescents with Cleft Lip and/or Palate: An Umbrella Review

Aim and objective

To assess the systematic reviews and meta-analyses investigating the dental caries experience in children with cleft lip and/or palate (CL/P).

Study design and methodology

A systematic search was carried out from MEDLINE Via PubMed, JBI Database of Systematic Reviews and Implementation Reports, EMBASE, OVID, Cochrane Database of Systematic Review, and Epistemonikos databases. Two independent reviewers carried out the collection and analysis of the study data. Methodological quality was assessed by ROBIS (Risk of bias assessment in systematic review) tool.

Review results

An initial search of electronic databases yielded a total of 25 relevant reviews, of which only three systematic reviews were taken into consideration for qualitative synthesis. The total number of unique primary studies among the three included systematic reviews were 25, of which overlap of the studies was calculated using citation matrix. The corrected covered area (CCA) was estimated to be 0.26. Based on the ROBIS tool, only one systematic review reported with low risk of bias.

Conclusion

Individuals with CL/P report more decayed, missing, or filled teeth/surfaces than those without CL/P in primary, mixed, and permanent dentition. Future studies should focus on the factors which could modify the caries risk of an individual with CL/P.

Clinical significance

This umbrella review offers a more reliable and balanced view regarding the dental caries experience among individuals with cleft lip and/or palate. This paper also highlights the important role of pediatric dentist in multidisciplinary health care team in implementing first dental visit and anticipatory guidance to consider early diagnosis and specific preventive interventions for Early Childhood Caries (ECC) in individuals with CL/P.

How to cite this article

Abirami S, Panchanadikar NT, Muthu MS, et al. Dental Caries Experience among Children and Adolescents with Cleft Lip and/or Palate: An Umbrella Review. Int J Clin Pediatr Dent 2022;15(S-2):S261-S268.

Dynamic Change in Oral Microbiota of Children With Cleft Lip and Palate After Alveolar Bone Grafting

To investigate the longitudinal influence of alveolar bone grafting on the oral microbiota of children with cleft lip and palate (CLP).

Twenty-eight children with nonsyndromic CLP were recruited and underwent secondary alveolar bone grafting at the first time. Unstimulated saliva and plaque samples were collected from the subjects preoperatively and at 2 days, 1 month, and 3 months postoperatively. The v3-v4 hypervariable regions of the 16S rRNA gene from bacterial DNA were sequenced using the Illumina MiSeq sequencing platform.

The alpha diversity of the saliva and plaque microbiota was significantly decreased at 2 days postoperatively and then increased at 1 and 3 months postoperatively. The saliva and plaque microbiota compositions at 2 days postoperatively differed from those at the other time points, and the microbiota compositions at 1 and 3 months postoperatively showed a gradual shift toward the preoperative composition. The saliva, but not plaque, microbiota composition 3 months postoperatively was similar to that preoperatively.

The effect of secondary alveolar bone grafting on the plaque microbiota in children with CLP lasted longer than the saliva microbiota. Alveolar bone grafting altered the saliva microbiota in children with CLP within 3 months postoperatively.

Comparative evaluation of nasal and alveolar changes in complete unilateral cleft lip and palate patients using intraoral and extraoral nasoalveolar molding techniques: randomized controlled trial

Objectives

Cleft lip and palate is a common congenital anomaly that impairs the aesthetics, speech, hearing, and psychological and social life of an individual. To achieve good aesthetic outcomes, presurgical nasoalveolar molding (NAM) has become important. Currently, the intraoral NAM technique is widely practiced. Numerous modifications have been made to intraoral NAM techniques, but the original problem of compliance leading to discontinuation of treatment remains unsolved. Therefore, the present study compared an extraoral NAM technique with the intraoral NAM technique.

Materials and Methods

Twenty infants with complete unilateral cleft lip and palate were included and divided into two equal groups. Group A received the intraoral NAM technique, and Group B received the extraoral NAM technique. Pre- and postoperative extraoral and intraoral measurements were recorded.

Results

Groups A and B did not differ significantly in any extraoral or intraoral parameter.

Conclusion

The extraoral NAM technique is as effective as the intraoral NAM technique in achieving significant nasal and alveolar changes in com-plete unilateral cleft lip and palate patients. Additionally, it reduces the need for frequent hospital visits for activation and the stress associated with the insertion and removal of the intraoral NAM plate, thereby improving compliance.

Effect of Sustained Interventions from Infancy to Toddlerhood in Children with Cleft Lip and Palate for Preventing Early Childhood Caries

The study aimed to evaluate the effectiveness of sustained interventions in children with cleft lip and palate (CLP) for preventing early childhood caries (ECC). This prospective, nonrandomized interventional cohort study was conducted in infants aged 0-12 months with congenital CLP. Interventions were given to parents/primary caregivers in the form of combined oral health-care measures (sterile wet gauze piece, finger brush, toothbrush, and toothpaste) by a motivational interviewing approach. Education of primary caregivers on oral hygiene was provided by audiovisual aids and demonstration. Reinforcement of the prescribed regimen was done through daily short message services in caregivers' preferred language and bimonthly telephone calls. Participants were followed up for 9-32 months from the time of recruitment, with a mean period of 18.3 ± 5.1 months. Rates of dental caries were represented as prevalence rates, incidence density, and transitional probability. The distribution of the International Caries Detection and Assessment System (ICDAS) scores on different tooth surfaces affected in the intervention group was compared descriptively with that of the age- and sex-matched historical control groups. On analysis of surface-wise distribution of the ICDAS scores in the intervention group (n = 1,919), 1.2% (n = 24) had noncavitated lesions (ICDAS codes 1 and 2), 0.88% (n = 17) had cavitated lesions (ICDAS codes 3-6), and 0.26% (n = 5) had both cavitated and noncavitated lesions (ICDAS codes 1-6). The incidence density of caries-affected children observed at the first and last follow-ups was 1.2 persons/100 person-months and 1.3 persons/100 person-months of observation, respectively. The incidence density of new caries-affected tooth surfaces at the first and last follow-ups was 0.163 surfaces/100 surface-months and 0.062 surfaces/100 surface-months, respectively. Maxillary first molars had the maximum transition from sound to the cavitated lesion (11.5%), followed by maxillary incisors from sound to noncavitated (7.5%) at the last follow-up. Based on the newly developed assessment criteria in our study, sustained interventions proved to be significantly effective in preventing ECC in children with CLP.

Profiling and Characterization of Localized Cytokine Response in Congenital Cleft Affected Lip Tissue

(1) Background: Despite cleft lips and palates belonging to the most common orofacial congenital anomalies, their morphopathogenesis is not yet fully understood. The study aimed to determine the distribution and relation of cytokines interferon-γ (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-2, IL-7, IL-12, and IL-13 in the cleft affected mucosa of the lip. (2) Materials and Methods: Twenty cleft lip (CL) mucosal samples and seven control tissues of oral cavity mucosa were included in the study. Specimen were obtained during reconstruction surgeries and processed by hematoxylin and eosin staining and immunohistochemistry for IFN-γ, TNF-α, IL-2, IL-7, IL-12, and IL-13. (3) Results: The distribution of cytokines was higher overall in the cleft affected epithelium compared to the connective tissue, with TNF-a, IL-2, and IL-12 displaying the highest number of immunopositive cells. With the exception of IL-2, CL specimen showed higher immunoreactivity. IFN-γ displayed only minor immunoreactivity, with no expression in the control epithelium. Correlation analysis was strongest between CL epithelial IL-13 and IFN-γ (z = 0.71, p < 0.0001). (4) Conclusions: The CLP affected epithelium displays high degrees of plasticity in expressing different cytokines, pointing towards the stimulation of a local adaptive immune response based on consistent inflammatory processes.

Salivary counts of Streptococcus mutans and Lactobacillus in patients with and without cleft lip and/or palate undergoing orthodontic treatment: A meta-analysis

OBJECTIVE

To conduct a systematic review with meta-analysis to assess if cleft lip and palate (CLP) patients undergoing orthodontic treatment have a higher colonization of Streptococcus mutans and Lactobacillus than patients without this condition.

METHODS

Five electronic databases were searched systematically. The inclusion criteria were as follows: randomized clinical trials, non-randomized, or quasi-randomized controlled trials, prospective and retrospective studies published until March, 2021; articles that evaluated S. mutans and Lactobacillus profile in patients with and without cleft lip and palate undergoing orthodontic treatment. The random-effect model was used to perform the analysis of all the data collected. Statistic heterogeneity was evaluated with I² test.

RESULTS

In this systematic review, 2 cohort studies were included. The data analysis from 160 patients revealed that patients without cleft lip and palate had 4.5 times more predisposition to oral colonization with S. mutans than CLP patients. No statistical significant difference was found between these patients for colonization with Lactobacillus.

CONCLUSIONS

Despite the limitations in the included studies, this systematic review suggested that CLP patients have a lower predisposition to oral colonization with S. mutans when compared to healthy patients.

Mucogingival Surgery in the Interdisciplinary Management of Patients with Palato-alveolar Cleft Defects

Here will present a mucogingival technique for interdisciplinary management in patients with palato-alveolar cleft defect sequelae. Mucogingival continuity is sought in these patients by means of an extended laterally positioned flap. Achieving a mucogingival seal in the cleft area would be of great value in interdisciplinary management, favoring the prognosis of subsequent treatments, such as alveolar bone grafts, orthodontics, and rehabilitation, to achieve more esthetic and functional and harmonious results for the patients' dentogingival complex.

Incidence of complications in secondary alveolar bone grafting of bilateral clefts with premaxillary osteotomy: a retrospective cohort study

OBJECTIVE

To evaluate factors affecting incidence of complications after secondary alveolar bone grafting with premaxillary osteotomy (SABG + PO) in children with complete bilateral cleft of lip and palate (BCLP).

MATERIALS AND METHODS

Data were collected from children with BCLP treated with SABG + PO from 2004 to 2014 at our institute. Preoperative parameters included age, donor site, race, gingival health, bone quality around cleft-related teeth, premaxilla position, graft timing, presence of canines in the cleft, and presence of deciduous teeth around the cleft area. Logistic regression and the chi-squared test were used to assess correlations and the incidence of complications.

RESULTS

In the 64 patients, a significant correlation was found between complication rate and timing of bone grafting with respect to early versus late SABG + PO (p = 0.041), age > 12 years (p = 0.011; odds ratio (OR) 5.9; 95% confidence interval (CI) 1.49-23.93), malposition of the premaxilla (p = 0.042; OR 3.3; 95% CI 1.04-10.13), and preoperative bone quality around cleft-related teeth (p = 0.005; OR 5.3; 95% CI 1.6-17.2).

CONCLUSIONS

The timing of SABG + PO is essential, as early SABG + PO is associated with fewer complications. A malpositioned premaxilla and poor bone quality around cleft-related teeth are associated with more complications. Therefore, preoperative orthodontic repositioning of the malpositioned premaxilla before SABG + PO should be considered.

CLINICAL RELEVANCE

Analysis of treatment protocols and complications for BCLP patients underscores that proper timing of SABG + PO and correct premaxilla repositioning help reduce complications.

Effects of cleft lip and palate on children's psychological health: A systematic review

OBJECTIVES

This study aimed to evaluate the psychological effects of cleft lip and palate (CLP) on children and their parents and to determine any relationship between social support and timing of surgical repairs for these defects.

METHODS

A systematic review that followed the problem, intervention, comparison, outcome and setting (PICOS) method was used. The participants were children with CLP, interventions were surgical corrections and/or social support, comparison occurred with children with neither surgical corrections nor social support, outcomes were psychological effects and the study design was a systematic review. Four electronic databases, EBSCO, ProQuest, Science Direct, and PsycInfo were used to search for studies over the period of ten years (January 2007 until January 2017). The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2009 guidelines on systematic review reporting were used for this study.

RESULTS

Searching through four databases revealed 53,346 articles; however, only 26 articles that met the inclusion criteria were included. There were few articles about children.

CONCLUSIONS

CLP is not only connected to psychological effects which distress children's self-esteem and psychological functions, it also extends to their parents, particularly their mothers. However, parental and social support seem to have positive influences by reducing these psychological effects.

Comparing caries risk profiles between 5- and 10- year-old children with cleft lip and/or palate and non-cleft controls

BACKGROUND

Previous studies have suggested that children with oral clefts may have higher caries prevalence in comparison with non-cleft controls but the relative importance of the potential risk factors is not clear. The aim of this study was to compare the caries risk profiles in a group of cleft lip and/or palate (CL(P)) children with non-cleft controls in the same age using a computerized caries risk assessment model.

METHODS

The study group consisted of 133 children with CL(P) (77 subjects aged 5 years and 56 aged 10 years) and 297 non-cleft controls (133 aged 5 years and 164 aged 10 years). A questionnaire was used to collect data concerning the child's oral hygiene routines, dietary habits and fluoride exposure. Oral hygiene was assessed using Quigley-Hein plaque Index and the caries prevalence and frequency was scored according to the International Caries Detection and Assessment System. Whole saliva samples were analyzed for mutans streptococci, lactobacilli, buffering capacity and secretion rate. The risk factors and risk profiles were compared between the groups with aid of Cariogram and the estimated risk for future caries was categorized as "high" or "low".

RESULTS

Children with CL(P) (the entire study group) had significantly higher counts of salivary lactobacilli (p < 0.05) and displayed less good oral hygiene (p < 0.05). More 10-year-old children in the CL(P) group had low secretion rate but this difference was not significant. The average chance to avoid caries ranged from 59 to 67% but there were no significant differences between the groups. The odds of being categorized with high caries risk in the CL(P) group was significantly elevated (OR = 1.89; 95% CI = 1.25-2.86). In both groups, children in the high risk category had a higher caries experience than those with low risk.

CONCLUSION

Children with CL(P) displayed increased odds of being categorized at high caries risk with impaired oral hygiene and elevated salivary lactobacilli counts as most influential factors. The results suggest that a caries risk assessment model should be applied in the routine CL(P) care as a basis for the clinical decision-making and implementation of primary and secondary caries prevention.

Comparison of risk indicators of dental caries in children with and without cleft lip and palate deformities

Objective:

To test the hypothesis that there are no differences in various risk factors of dental caries among children with cleft lip and palate when compared to non-cleft high caries risk and non-cleft caries free children.

Design:

Seventy-three children in the age range of 4–9 years comprised three groups; Group-I (n = 23, children with cleft lip and palate), Group-II (n = 25, non-cleft high caries risk children) and Group-III (n = 25, non-cleft caries free children). Various risk factors for dental caries like type of oral hygiene practice, sugar exposures/day, developmental defects of enamel, caries activity, salivary streptococci mutans levels and lactobacilli levels were evaluated and compared among the three groups of children.

Results:

The mean deft score among Group-II children was significantly more (P < 0.01) as compared to the Group-I children. The mean deft + DMFT score among Group-I and Group-II children was comparable (P = 0.149). Developmental enamel defects were more among Group-I children as compared to Group-II and Group-III children (P < 0.01). Hypoplasia of the maxillary anterior teeth was more common among Group-I children as compared to Group-II (P < 0.05) and Group-III children (P < 0.001). The association between hypoplastic teeth and dental caries was significant (P < 0.05). The salivary acidogenic potential as evaluated by Snyder test was comparable among Group-I and Group-II children. The salivary streptococcus mutans levels in Group-I and Group-II children were higher when compared to lactobacillus counts.

Conclusion:

The risk factors of dental caries among children with cleft lip and palate were more as compared to non-cleft high caries risk and non-cleft caries free children.

Comparison of oral hygiene and periodontal status in patients with clefts of palate and patients with unilateral cleft lip, palate and alveolus

Aim:

This study was conducted to analyze and compare the oral hygiene and periodontal status in patients with clefts of palate (CP) and patients with unilateral cleft lip, palate and alveolus (UCLPA).

Materials and Methods:

The study group consisted of 120 cleft patients. Subjects were divided into two groups of 60 each. Group I - patients with UCLPA and Group II - patients with CP. For comparison, all the four quadrants were defined, Q1-right upper quadrant, Q2-left upper quadrant, Q3-left lower quadrant and Q4-right lower quadrant, in both groups and the following parameters were recorded: Plaque Index (PI, Silness and Loe), Sulcus Bleeding Index (SBI, Muhlemann and Son), Probing Pocket Depth (PPD), Clinical Attachment Level (CAL), Mobility Index (Miller) and Radiographic Amount of Bone Loss.

Results:

The periodontal destruction was seen to be higher in UCLPA patients compared with CP patients. The poor oral hygiene status, as indicated by higher values of PI, and the periodontal status, evaluated by SBI, PPD, CAL, mobility and Radiographic Amount of Bone Loss, were higher in patients with UCLPA than in patients with CP.

Conclusion:

In this study, patients with cleft lip, palate and alveolus had poor oral hygiene and periodontal status compared with patients with cleft palate.

Women are more susceptible to caries but individuals born with clefts are not

The identification of individuals at a higher risk of developing caries is of great interest. Isolated forms of cleft lip and palate are among the most common craniofacial congenital anomalies in humans. Historically, several reports suggest that individuals born with clefts have a higher risk for caries. Caries continues to be the most common infectious noncontagious disease worldwide and a great burden to any health system. The identification of individuals of higher susceptibility to caries is of great interest. In this paper, we assessed caries experience of 1,593 individuals from three distinct populations. The study included individuals born with clefts, their unaffected relatives, and unrelated unaffected controls that were recruited from areas with similar cultural pressures and limited access to dental care. DMFT/dmft scores were obtained, and caries experience rates were compared among the three groups in each geographic area. Individuals born with clefts did not present higher caries experience in comparison to their unaffected relatives or unrelated unaffected controls. Women tend to present higher caries rates in comparison to men. Our work provides strong evidence that individuals born with clefts are not at higher risk to caries; however, women tend to have more severe caries experience.

Dental caries prevalence in children with cleft lip/palate aged between 6 months and 6 years in the West of Scotland

AIM

To compare the prevalence of dental caries in children with cleft lip/palate with national data at the same age.

METHOD

Ethical approval was granted from the West of Scotland Ethics Committee. Children attending the Oral Orthopaedic Clinic were examined for caries according to the criteria of the British Association for the Study of Community Dentistry (BASCD) by two trained and calibrated examiners (KB, RW). Subjects were divided into five age groups: 0.5-1.49; 1.5-2.49; 2.5-3.49; 3.5-4.49 and 4.5-6.0 years. Mean dmft scores were compared with available national data (National Dental Inspection Program of Scotland) for nursery [NDIP 3-year-old survey 2008, unpublished] and 5-year-old children in Scotland [NDIP, 2008].

RESULTS

209 subjects were examined (participation rate of 87.4%); 45.9% were female, 54.1% male; 21 children (10%) had a recognised syndrome and were reported separately. Cleft Palate (CP) was the most commonly occurring cleft in both syndromic and non-syndromic groups, followed in decreasing numbers by Unilateral Cleft Lip and Palate (UCLP), Bilateral Cleft Lip and Palate (BCLP), Unilateral Cleft Lip (UCL) and Bilateral Cleft Lip (BCL). The only age group with a significantly higher level of dental caries compared with national data was the 4.5-6.0 year-olds where only 37.2% of the children with clefts were caries free compared with the national figure of 57.7% (p=0.004). This same age group had a mean dmft for the cleft group of 3.24 compared with 1.86 nationally. The other age groups had similar dmft and percentages of subjects caries free compared with the national data. The differences did not reach significance. Caries was more common in the anterior teeth of the youngest two age groups, but in the posterior teeth of the two oldest age groups.

CONCLUSION

By the age of 4.5 years, children with cleft lip/palate in the West of Scotland have significantly more caries than their non-cleft peers.

Comparison of periodontal status among patients with cleft lip, cleft palate, and cleft lip along with a cleft in palate and alveolus

BACKGROUND AND OBJECTIVES

A healthy periodontium is an important prerequisite for unhindered dentition and long-term oral health. In cleft subjects, especially in those with cleft lip, alveolus and palate (CLAP), maintenance of oral hygiene is a difficult task for the patients because of the patent oro-nasal communication. Crowding of teeth in cleft patients is a common finding, especially in those with CLAP and those with cleft palate (CP). In the case of multiple tooth-malpositions, transverse deficiency, arch length deficiency and primary cross-bite; periodontal trauma increases and is detrimental to periodontal health. According to literature, a critical periodontal situation was found in patients with CLAP. Hence a study was conducted to analyze the periodontal status of patients with cleft lip (CL); those with cleft palate; and those with cleft lip, alveolus and palate.

MATERIALS AND METHODS

The present study consisted of 60 cleft subjects divided into 3 groups: those with cleft lip; those with cleft palate; and those with cleft lip, alveolus and palate. Subjects with permanent dentition were selected, and the clinical examination included determination of oral hygiene status using Oral Hygiene Index - Simplified (OHI-S) index and periodontal status using community periodontal index (CPI).

RESULTS

Statistically significant increase in the periodontal disease in the CLAP group as compared with the other 2 groups, and the oral hygiene was seen to be generally poor with the CLAP group.

INTERPRETATION AND CONCLUSION

Individuals with clefts are more prone to periodontal disease due to the presence of cleft, which causes retention of food in the defect sites and inability to maintain good oral hygiene; but the severity of periodontal disease is more if the defect is large and involving the lip, alveolus and palate.

Discovery of candidate disease genes in ENU-induced mouse mutants by large-scale sequencing, including a splice-site mutation in nucleoredoxin

An accurate and precisely annotated genome assembly is a fundamental requirement for functional genomic analysis. Here, the complete DNA sequence and gene annotation of mouse Chromosome 11 was used to test the efficacy of large-scale sequencing for mutation identification. We re-sequenced the 14,000 annotated exons and boundaries from over 900 genes in 41 recessive mutant mouse lines that were isolated in an N-ethyl-N-nitrosourea (ENU) mutation screen targeted to mouse Chromosome 11. Fifty-nine sequence variants were identified in 55 genes from 31 mutant lines. 39% of the lesions lie in coding sequences and create primarily missense mutations. The other 61% lie in noncoding regions, many of them in highly conserved sequences. A lesion in the perinatal lethal line l11Jus13 alters a consensus splice site of nucleoredoxin (Nxn), inserting 10 amino acids into the resulting protein. We conclude that point mutations can be accurately and sensitively recovered by large-scale sequencing, and that conserved noncoding regions should be included for disease mutation identification. Only seven of the candidate genes we report have been previously targeted by mutation in mice or rats, showing that despite ongoing efforts to functionally annotate genes in the mammalian genome, an enormous gap remains between phenotype and function. Our data show that the classical positional mapping approach of disease mutation identification can be extended to large target regions using high-throughput sequencing.