Genetics and management of the patient with orofacial cleft

Need for orthognathic surgery in cleft patients from Northern Finland

OBJECTIVE

Northern Finland has a unique distribution of clefts compared to the rest of Europe and Finland. This may reflect the need for orthognathic surgery among Northern Finland's patient pool. The aim of this study was to compare previously operated patients aged 18 years or older with cleft lip, cleft lip and alveolus, cleft lip and palate, cleft palate and to evaluate the need for orthognathic surgery in order to achieve a stable and functional occlusion.  Materials and methods: The study group consisted of all 18-years-old cleft patients treated in the Oulu Cleft Center. The total amount of patients was 110. The patients were compared retrospectively using patients' hospital records. The majority of patients did not have any cleft-associated syndrome. The need for maxillary or bimaxillary orthognathic or corrective-jaw surgery was evaluated by the Oulu Cleft Team. A descriptive and statistical analysis was used to determine the need for orthognathic surgery according to sex and cleft type.

RESULTS

There were nineteen patients of the total of 110 patients who met the criteria requiring corrective-jaw surgery (17,3%). In total 12 males (25,0%) and 7 females (11,3%) were evaluated for the need of orthognathic surgery. Sixteen of the 19 patients had palatal involvement of the cleft.

CONCLUSIONS

The need for orthognathic surgery was greater in the cleft lip palate and cleft palate patient groups compared to cleft lip alveolus or cleft lip groups. This study also found that males from Northern Finland need surgery more often than females.

Impact of relaxing incisions on maxillofacial growth following Sommerlad-Furlow modified technique in patients with isolated cleft palate: a preliminary comparative study

OBJECTIVE

To estimate the impact of relaxing incisions on maxillofacial growth following Sommerlad-Furlow modified technique in patients with isolated cleft palate.

STUDY DESIGN

A Retrospective Cohort Study.

METHODS

A total of 90 participants, 60 patients with non-syndromic isolated soft and hard cleft palate underwent primary palatoplasty (30 patients received the Sommerlad-Furlow modified technique without relaxing incision (S.F-RI group), and 30 received Sommerlad-Furlow modified technique with relaxing (S.F+RI group) with no significant difference found between them regarding the cleft type, cleft width, and age at repair. While the other 30 were healthy noncleft participants with skeletal class I pattern as a Control group. The control group (C group) was matched with the patient groups in number, age, and sex. All participants had lateral cephalometric radiographs at least 5 years old age. The lateral cephalometric radiographs were taken with the same equipment by the same experienced radiologist while the participants were in centric occlusion and a standardized upright position, with the transporionic axis and Frankfort horizontal plane parallel to the surface of the floor. A well-trained assessor (S. Elayah) used DOLPHIN Imaging Software to trace twice to eliminate measurement errors. All the study variables were measured using stable landmarks, including 12 linear and 10 angular variants.

RESULTS

The mean age at collection of cephalograms was 6.03 ± 0.80 in the S.F+RI group, 5.96 ± 0.76 in the S.F-RI group, and 5.91 ± 0.87 in the C group. Regarding cranial base, the results showed no statistically significant differences between the three groups in S-N and S-N-Ba. While the S.F+R.I group had a significantly shortest S-Ba than the S.F-R.I & C groups (P = 0.01 & P < 0.01), but there was no statistically significant difference between S.F-R.I & C groups (P = 0.71). Regarding the skeletal maxilla, there was no significant difference between the S.F+R.I and S.F-R.I groups in all linear measurements (N-ANS and S-PM) except Co-A, the S.F+R.I group had significantly shorter Co-A than the S.F-R.I & C groups (P =  < 0.01). While the angular measurement, S.F+R.I group had significantly less SNA angle than the S.F-R.I & C groups (P =  < 0.01). Regarding mandibular bone, there were no statistically significant differences in all linear and angular mandibular measurements between the S.F+R.I and S.F-R.I.groups. Regarding intermaxillary relation, the S.F+R.I group had significant differences in Co-Gn-Co-A and ANB compared to the S.F-R.I & C groups (P =  < 0.01). While there was no statistically significant difference in PP-MP between the three groups.

CONCLUSION

As a preliminary report, the Sommerlad-Furlow modified technique without relaxing incisions was found to have a good maxillary positioning in the face and a satisfactory intermaxillary relationship compared to the Sommerlad-Furlow modified technique with relaxing incisions.

A Surgical Complexity Factor for Clefts of Primary and Secondary Palates

The surgical treatment of patients with cleft lip and palate depends on the characteristics of the affected anatomical structures (palate, lip and nose). The objective of this work was to develop a quantified classification for these clefts, to represent their surgical complexity. This work was developed with the team of surgeons of the SUMA Cleft Leadership Center (CLC) Smile Train Mexico. The method of Multiple-Criteria Decision Analysis was applied using the Analytic Hierarchy Approach. A surgical complexity factor associated with each cleft was defined and it was validated in a sample of fifty patients treated at the SUMA-CLC.Clinical Relevance- A quantitative classification that represents the surgical complexity of clefts provides an objective unified criteria for planning the surgical treatment of patients, as well as having standardized procedures for the surgical treatment of patients.

[Cleft lip and palate : One of the most frequent congenital malformations]

With a frequency of 1 per 500 live births, a cleft lip and palate is one of the most frequent congenital malformations. Untreated, it leads to disturbances in feeding, speech, hearing, tooth position and esthetics. A multifactorial genesis is assumed. The fusion of the different facial processes takes place in the first 3 months of pregnancy and a cleft can develop during this time. Surgical treatment includes the early anatomical and functional restoration of the affected structures within the first year of life in order to enable normal intake of food, articulation, nasal breathing and middle ear ventilation. Breastfeeding is possible in children with a cleft formation but alternative feeding methods, such as finger feeding, often have to be used. In addition to the surgery for primary closure of the cleft, otorhinolaryngological (ENT) interventions, speech therapy, orthodontic treatment as well as other surgical interventions are part of the interdisciplinary treatment concept.

Assessment of orthodontic treatment outcome using Peer Assessment Rating (PAR) index among patients with non-syndromic unilateral cleft lip and palate

OBJECTIVE:

To evaluate the orthodontic treatment outcome among patients with non-syndromic unilateral cleft lip and palate using the Peer Assessment Rating (PAR) index.

MATERIALS AND METHODS:

The retrospective study comprised a sample of 80 patients with unilateral cleft lip and palate (39 males and 41 females) with complete pretreatment and posttreatment orthodontic records. The patients were divided into two groups according to the treatment modalities. Group 1 (n = 55), nonsurgical (consisted of patients treated with comprehensive orthodontics) and Group 2 (n = 25), surgical (with presurgical orthodontics followed by maxillary advancement orthognathic surgery). PAR score was evaluated on pretreatment and posttreatment study models for both groups.

RESULTS:

The mean percentage change for the weighted PAR score of Group 1 and Group 2 was 76.79 ± 20.27% and 82.37 ± 11.38%, respectively. Out of the total sample of 80 cases; 62 (77.5%) cases were “greatly improved,” 16 (20%) cases were “improved,” and 2 (2.5%) showed “worse/no improvement.” Nearly 72.5% of cases in Group 1 and 88% in Group 2 were greatly improved.

CONCLUSIONS:

The reduction in PAR score in both groups was satisfactory as more than 70% of the patients were in the greatly improved category. The results of the PAR index revealed a high occlusal outcome of orthodontic treatment rendered by the department for patients with unilateral cleft lip and palate.

Medicines associated with folate-homocysteine-methionine pathway disruption

Folate is vital for cell development and growth. It is involved in one-carbon transfer reactions essential for the synthesis of purines and pyrimidines. It also acts in conjunction with cobalamin (vitamin B₁₂) as a fundamental cofactor in the remethylation cycle that converts homocysteine to methionine. A deficiency in folate or vitamin B₁₂ can lead to elevated homocysteine level, which has been identified as an independent risk factor in several health-related conditions. Adequate folate levels are essential in women of childbearing age and in pregnant women, and folate deficiency is associated with several congenital malformations. Low folate levels can be caused by dietary deficiencies, a genetic predisposition or treatment with medicines that affect folate concentration. Women who are pregnant or of child-bearing age commonly use medicines, so it is important to identify the basic biochemical mechanisms by which medicines interfere with the folate-homocysteine-methionine pathway. This review focuses on prescription medicines associated with folate disruption. It also summarizes their undesirable/toxic effects. Recommendations regarding folate supplementation during medical therapy are also reviewed.

22q11.2 Deletion Syndrome in Colombian Patients With Syndromic Cleft Lip and/or Palate

The objective of this work was to identify 22q11.2 chromosomal deletion in patients with cleft lip and/or cleft palate and suggestive syndromic phenotype in Colombian patients. We studied 49 patients with cleft lip and/or cleft palate, exhibiting additional clinical findings linked to 22q11.2 deletion syndrome. All patients underwent high-resolution G-banded karyotyping, multiplex ligation-dependent probe amplification, and clinical evaluation by a geneticist. Seven patients presented 22q11.2 deletion and 2 patients had other chromosomal abnormalities. In conclusion, this study contributes with new data for genetic etiology in syndromic conditions of oral fissures.

Differential methylation is associated with non-syndromic cleft lip and palate and contributes to penetrance effects

Non-syndromic cleft lip and/or palate (NSCLP) is a common congenital malformation with a multifactorial model of inheritance. Although several at-risk alleles have been identified, they do not completely explain the high heritability. We postulate that epigenetic factors as DNA methylation might contribute to this missing heritability. Using a Methylome-wide association study in a Brazilian cohort (67 NSCLP, 59 controls), we found 578 methylation variable positions (MVPs) that were significantly associated with NSCLP. MVPs were enriched in regulatory and active regions of the genome and in pathways already implicated in craniofacial development. In an independent UK cohort (171 NSCLP, 177 controls), we replicated 4 out of 11 tested MVPs. We demonstrated a significant positive correlation between blood and lip tissue DNA methylation, indicating blood as a suitable tissue for NSCLP methylation studies. Next, we quantified CDH1 promoter methylation levels in CDH1 mutation-positive families, including penetrants, non-penetrants or non-carriers for NSCLP. We found methylation levels to be significantly higher in the penetrant individuals. Taken together, our results demonstrated the association of methylation at specific genomic locations as contributing factors to both non-familial and familial NSCLP and altered DNA methylation may be a second hit contributing to penetrance.

Nonsynonymous variants in MYH9 and ABCA4 are the most frequent risk loci associated with nonsyndromic orofacial cleft in Taiwanese population

BACKGROUND

Nonsyndromic orofacial cleft is a common birth defect with a complex etiology, including multiple genetic and environmental risk factors. Recent whole genome analyses suggested associations between nonsyndromic orofacial cleft and up to 18 genetic risk loci (ABCA4, BMP4, CRISPLD2, GSTT1, FGF8, FGFR2, FOXE1, IRF6, MAFB, MSX1, MTHFR, MYH9, PDGFC, PVRL1, SUMO1, TGFA, TGFB3, and VAX1), each of which confers a different relative risk in different populations. We evaluate the nonsynonymous variants in these 18 genetic risk loci in nonsyndromic orofacial clefts and normal controls to clarify the specific variants in Taiwanese population.

METHODS

We evaluated these 18 genetic risk loci in 103 cases of nonsyndromic orofacial clefts and 100 normal controls using a next-generation sequencing (NGS) customized panel and manipulated a whole-exon targeted-sequencing study based on the NGS system of an Ion Torrent Personal Genome Machine (IT-PGM). IT-PGM data processing, including alignment with the human genome build 19 reference genome (hg19), base calling, trimming of barcoded adapter sequences, and filtering of poor signal reads, was performed using the IT platform-specific pipeline software Torrent Suite, version 4.2, with the plug-in "variant caller" program. Further advanced annotation was facilitated by uploading the exported VCF file from Variant Caller to the commercial software package Ion Reporter; the free online annotation software Vanno and Mutation Taster. Benign or tolerated amino acid changes were excluded after analysis using sorting intolerant from tolerant and polymorphism phenotyping. Sanger sequencing was used to validate the significant variants identified by NGS. Furthermore, each variant was confirmed in asymptomatic controls using the Sequenom MassARRAY (San Diego, CA, USA).

RESULTS

We identified totally 22 types of nonsynonymous variants specific in nonsyndromic orofacial clefts, including 19 single nucleotide variants, 2 deletions, and 1 duplication in 10 studied genes(ABCA4, MYH9, MTHFR, CRISPLD2, FGF8, PVRL1, FOXE1, VAX1, FGFR2, and IRF6). Nonsynonymous variants in MYH9 and ABCA4, which were detected in 6 and 5 individuals, respectively, were identified to be the most frequent risk loci in nonsyndromic orofacial clefts in the Taiwanese population.

CONCLUSIONS

Nonsynonymous variants in MYH9 and ABCA4 were identified to be the most frequent risk loci in nonsyndromic orofacial clefts in the Taiwanese population. These findings in our study have provided additional information regarding specific variants associated with nonsyndromic orofacial clefts in different population and demonstrate the power of our customized NGS panel, which is clinically useful for the simultaneous detection of multiple genes associated with nonsyndromic orofacial clefts.

Epidemiology, Etiology, and Treatment of Isolated Cleft Palate

Isolated cleft palate (CPO) is the rarest form of oral clefting. The incidence of CPO varies substantially by geography from 1.3 to 25.3 per 10,000 live births, with the highest rates in British Columbia, Canada and the lowest rates in Nigeria, Africa. Stratified by ethnicity/race, the highest rates of CPO are observed in non-Hispanic Whites and the lowest in Africans; nevertheless, rates of CPO are consistently higher in females compared to males. Approximately fifty percent of cases born with cleft palate occur as part of a known genetic syndrome or with another malformation (e.g., congenital heart defects) and the other half occur as solitary defects, referred to often as non-syndromic clefts. The etiology of CPO is multifactorial involving genetic and environmental risk factors. Several animal models have yielded insight into the molecular pathways responsible for proper closure of the palate, including the BMP, TGF-β, and SHH signaling pathways. In terms of environmental exposures, only maternal tobacco smoke has been found to be strongly associated with CPO. Some studies have suggested that maternal glucocorticoid exposure may also be important. Clearly, there is a need for larger epidemiologic studies to further investigate both genetic and environmental risk factors and gene-environment interactions. In terms of treatment, there is a need for long-term comprehensive care including surgical, dental and speech pathology. Overall, five main themes emerge as critical in advancing research: (1) monitoring of the occurrence of CPO (capacity building); (2) detailed phenotyping of the severity (biology); (3) understanding of the genetic and environmental risk factors (primary prevention); (4) access to early detection and multidisciplinary treatment (clinical services); and (5) understanding predictors of recurrence and possible interventions among families with a child with CPO (secondary prevention).

Assessment of folic Acid and DNA damage in cleft lip and cleft palate

Studies have identified the risk factors like folic acid deficiency during gestational period, family history for orofacial clefts, drugs like antiepileptic, vitamin A. But, the data regarding the folic acid status in children with cleft lip/palate is hardly evaluated in depth. Here, an assessment of folic acid and DNA damage were carried out in children with orofacial anomalies. Folic acid level and DNA damage were evaluated by folic acid assay (direct chemiluminescent technology) and single cell gel electrophoresis or comet assay method respectively. The mean value of plasma folic acid by direct chemiluminescent technology was 6.5±3.6 nmol/L and the normal value in children ranges from 11.3 to 47.6 nmol/L. The amount of damaged DNA, measured as the tail length of the comet in cases, was 19.4±8.9 μm and the mean percentage of DNA in tail was 16.5±3.7. Folic acid deficiency could be the reason for DNA damage.