Techniques and timings for cleft palate surgery: a randomised controlled trial

Background: There is a lack of reliable information on outcomes following cleft surgery. Options for timing and choice of primary cleft surgery had not been compared in randomised trials. Methods: Non-syndromic infants, aged six months, with isolated cleft of the secondary palate without associated lip deformity, were included in this prospective randomised controlled trial to one of four options: Veau-Wardill-Kilner palatoplasty at six (VWK06) or 12 months of age (VWK12), or two-flap palatoplasty with intra-velar veloplasty at six (2F-IVV06) or 12 months of age (2F-IVV12).  Results: Of the 76 infants included in the trial, 90.8 per cent received surgery: VWK06 (n=18), VWK12 (n=16), 2F-IVV06 (n=18) and 2F-IVV12 (n=17). Early postoperative complications occurred in two VWK infants (6.1%) and three 2F-IVV infants (8.8%). With surgery planned at six (T06) and 12 months of age (T12) respectively, there were three VWK infants (8.6%) and two 2F-IVV infants (6.3%). At age three, speech assessments were conducted for 62 (84%) children. Velopharyngeal inadequacy symptoms were detected in 4/30 VWK children (13.3%) and 3/30 2F-IVV children (10.0%). With T06 and T12, there were three VWK infants (9.4%) and four 2F-IVV infants (14.3%). Otitis media was documented in 40/61 of children (65.6%) hyper- and/or hyponasality in 27/61 of children (44%) and articulation errors in 53/60 of children (88%). Conclusion: Postsurgical complication rates differ little between VWK and 2F-IVV. At three years, there were no demonstrable differences in velopharyngeal inadequacy symptoms, nasality, articulation and otitis media between the two surgical techniques at two different times.

Results of Primary Repair of Submucous Cleft Palate with Furlow Palatoplasty in Both Syndromic and Nonsyndromic Children

Objective

We hypothesize that primary repair of submucous cleft palate (SMCP) with Furlow palatoplasty will not lead to significant differences in speech outcomes for syndromic and nonsyndromic children.

Design

Retrospective analysis of patients with primary Furlow repair of SMCP between 2004 and 2012.

Setting

Tertiary care center.

Patients/Participants

Thirty-four patients (15 boys; 44%) satisfied our inclusion criteria: multidisciplinary consensus on diagnosis of SMCP, failed trial of speech-language rehabilitation, at least 4 years old at the time of primary surgery, at least 6 months follow-up with a repeat set of postoperative speech assessments.

Interventions

Primary Furlow palatoplasty for SMCP.

Main Outcome Measures

Primary outcomes were based on postoperative perceptual speech assessments and the need for revision surgery. Secondary outcomes included improvement in nasalance scores, postoperative complications, and change in and time to normalization of velar closing ratios.

Results

Mean age at surgery = 7.7 years. Of the patients, 17 (50%) were syndromic and 11 (32%) had associated hearing loss. Mean follow-up = 48 months. No patients had postoperative complications, such as wound dehiscence or fistula; however, two patients (one syndromic, one nonsyndromic) required secondary procedures. Velar closing ratios for all patients increased ( P < .05) and approached normal at an average of 1.3 years postoperatively.

Conclusions

Although the Furlow palatoplasty can correct anatomic anomalies, it cannot achieve normal perceptual resonance in syndromic patients, possibly because of inherent higher-order deficiencies that affect speech production. Further studies with greater patient numbers are necessary to achieve population statistical significance.

Novel evidence of association with nonsyndromic cleft lip with or without cleft palate was shown for single nucleotide polymorphisms in FOXF2 gene in an Asian population

BACKGROUND

The forkhead box F2 gene (FOXF2) located in chromosome 6p25.3 has been shown to play a crucial role in palatal development in mouse and rat models. To date, no evidence of linkage or association has been reported for this gene in humans with oral clefts.

METHODS

Allelic transmission disequilibrium tests were used to robustly assess evidence of linkage and association with nonsyndromic cleft lip with or without cleft palate for nine single nucleotide polymorphisms (SNPs) in and around FOXF2 in both Asian and European trios using PLINK.

RESULTS

Statistically significant evidence of linkage and association was shown for two SNPs (rs1711968 and rs732835) in 216 Asian trios where the empiric P values with permutation tests were 0.0016 and 0.005, respectively. The corresponding estimated odds ratios for carrying the minor allele at these SNPs were 2.05 (95% confidence interval = 1.41, 2.98) and 1.77 (95% confidence interval = 1.26, 2.49), respectively.

CONCLUSION

Our results provided statistical evidence of linkage and association between FOXF2 and nonsyndromic cleft lip with or without cleft palate.

Evidence of gene-environment interaction for two genes on chromosome 4 and environmental tobacco smoke in controlling the risk of nonsyndromic cleft palate

Nonsyndromic cleft palate (CP) is one of the most common human birth defects and both genetic and environmental risk factors contribute to its etiology. We conducted a genome-wide association study (GWAS) using 550 CP case-parent trios ascertained in an international consortium. Stratified analysis among trios with different ancestries was performed to test for GxE interactions with common maternal exposures using conditional logistic regression models. While no single nucleotide polymorphism (SNP) achieved genome-wide significance when considered alone, markers in SLC2A9 and the neighboring WDR1 on chromosome 4p16.1 gave suggestive evidence of gene-environment interaction with environmental tobacco smoke (ETS) among 259 Asian trios when the models included a term for GxE interaction. Multiple SNPs in these two genes were associated with increased risk of nonsyndromic CP if the mother was exposed to ETS during the peri-conceptual period (3 months prior to conception through the first trimester). When maternal ETS was considered, fifteen of 135 SNPs mapping to SLC2A9 and 9 of 59 SNPs in WDR1 gave P values approaching genome-wide significance (10(-6)<P<10(-4)) in a test for GxETS interaction. SNPs rs3733585 and rs12508991 in SLC2A9 yielded P = 2.26×10(-7) in a test for GxETS interaction. SNPs rs6820756 and rs7699512 in WDR1 also yielded P = 1.79×10(-7) and P = 1.98×10(-7) in a 1 df test for GxE interaction. Although further replication studies are critical to confirming these findings, these results illustrate how genetic associations for nonsyndromic CP can be missed if potential GxE interaction is not taken into account, and this study suggest SLC2A9 and WDR1 should be considered as candidate genes for CP.

X-linked markers in the Duchenne muscular dystrophy gene associated with oral clefts

As part of an international consortium, case-parent trios were collected for a genome-wide association study of isolated, non-syndromic oral clefts, including cleft lip (CL), cleft palate (CP), and cleft lip and palate (CLP). Non-syndromic oral clefts have a complex and heterogeneous etiology. Risk is influenced by genes and environmental factors, and differs markedly by gender. Family-based association tests (FBAT) were used on 14,486 single nucleotide polymorphisms (SNPs) spanning the X chromosome, stratified by type of cleft and racial group. Significant results, even after multiple-comparisons correction, were obtained for the Duchenne muscular dystrophy (DMD) gene, the largest single gene in the human genome, among CL/P (i.e., both CL and CLP combined) trios. When stratified into groups of European and Asian ancestry, stronger signals were obtained for Asian subjects. Although conventional sliding-window haplotype analysis showed no increase in significance, selected combinations of the 25 most significant SNPs in the DMD gene identified four SNPs together that attained genome-wide significance among Asian CL/P trios, raising the possibility of interaction between distant SNPs within the DMD gene.

Examining markers in 8q24 to explain differences in evidence for association with cleft lip with/without cleft palate between Asians and Europeans

In a recent genome-wide association study (GWAS) from an international consortium, evidence of linkage and association in chr8q24 was much stronger among nonsyndromic cleft lip/palate (CL/P) case-parent trios of European ancestry than among trios of Asian ancestry. We examined marker information content and haplotype diversity across 13 recruitment sites (from Europe, United States, and Asia) separately, and conducted principal components analysis (PCA) on parents. As expected, PCA revealed large genetic distances between Europeans and Asians, and a north-south cline from Korea to Singapore in Asia, with Filipino parents forming a somewhat distinct Southeast Asian cluster. Hierarchical clustering of SNP heterozygosity revealed two major clades consistent with PCA results. All genotyped SNPs giving P < 10(-6) in the allelic transmission disequilibrium test (TDT) showed higher heterozygosity in Europeans than Asians. On average, European ancestry parents had higher haplotype diversity than Asians. Imputing additional variants across chr8q24 increased the strength of statistical evidence among Europeans and also revealed a significant signal among Asians (although it did not reach genome-wide significance). Tests for SNP-population interaction were negative, indicating the lack of strong signal for 8q24 in families of Asian ancestry was not due to any distinct genetic effect, but could simply reflect low power due to lower allele frequencies in Asians.

BMP4 was associated with NSCL/P in an Asian population

BACKGROUND

The Bone Morphogenetic Protein 4 gene (BMP4) is located in chromosome 14q22-q23 which has shown evidence of linkage for isolated nonsyndromic cleft lip with or without cleft palate (NSCL/P) in a genome wide linkage analysis of human multiplex families. BMP4 has been shown to play crucial roles in lip and palatal development in animal models. Several candidate gene association analyses also supported its potential risk for NSCL/P, however, results across these association studies have been inconsistent. The aim of the current study was to test for possible association between markers in and around the BMP4 gene and NSCL/P in Asian and Maryland trios.

METHODOLOGY/PRINCIPAL FINDINGS

Family Based Association Test was used to test for deviation from Mendelian assortment for 12 SNPs in and around BMP4. Nominal significant evidence of linkage and association was seen for three SNPs (rs10130587, rs2738265 and rs2761887) in 221 Asian trios and for one SNP (rs762642) in 76 Maryland trios. Statistical significance still held for rs10130587 after Bonferroni correction (corrected p = 0.019) among the Asian group. Estimated odds ratio for carrying the apparent high risk allele at this SNP was 1.61 (95%CI = 1.20, 2.18).

CONCLUSIONS

Our results provided further evidence of association between BMP4 and NSCL/P.

Genome wide study of maternal and parent-of-origin effects on the etiology of orofacial clefts

We performed a genome wide association analysis of maternally-mediated genetic effects and parent-of-origin (POO) effects on risk of orofacial clefting (OC) using over 2,000 case-parent triads collected through an international cleft consortium. We used log-linear regression models to test individual SNPs. For SNPs with a P-value <10(-5) for maternal genotypic effects, we also applied a haplotype-based method, TRIMM, to extract potential information from clusters of correlated SNPs. None of the SNPs were significant at the genome wide level. Our results suggest neither maternal genome nor POO effects play major roles in the etiology of OC in our sample. This finding is consistent with previous genetic studies and recent population-based cohort studies in Norway and Denmark, which showed no apparent difference between mother-to-offspring and father-to-offspring recurrence of clefting. We, however, cannot completely rule out maternal genome or POO effects as risk factors because very small effects might not be detectable with our sample size, they may influence risk through interactions with environmental exposures or may act through a more complex network of interacting genes. Thus, the most promising SNPs identified by this study may still be worth further investigation.

ROR2 gene is associated with risk of non-syndromic cleft palate in an Asian population

BACKGROUND

The receptor tyrosine kinase-like orphan receptor 2 (ROR2) gene has been recently shown to play important roles in palatal development in animal models and resides in the chromosomal region linked to non syndromic cleft lip with or without cleft palate in humans. The aim of this study was to investigate the possible association between ROR2 gene and non-syndromic oral clefts.

METHODS

Here we tested 38 eligible single-nucleotide polymorphisms (SNPs) in ROR2 gene in 297 non-syndromic cleft lip with or without cleft palate and in 82 non-syndromic cleft palate case parent trios recruited from Asia and Maryland. Family Based Association Test was used to test for deviation from Mendelian inheritance. Plink software was used to test potential parent of origin effect. Possible maternally mediated in utero effects were assessed using the TRIad Multi-Marker approach under an assumption of mating symmetry in the population.

RESULTS

Significant evidence of linkage and association was shown for 3 SNPs (rs7858435, rs10820914 and rs3905385) among 57 Asian non-syndromic cleft palate trios in Family Based Association Tests. P values for these 3 SNPs equaled to 0.000068, 0.000115 and 0.000464 respectively which were all less than the significance level (0.05/38 = 0.0013) adjusted by strict Bonferroni correction. Relevant odds ratios for the risk allele were 3.42 (1.80 - 6.50), 3.45 (1.75 - 6.67) and 2.94 (1.56 - 5.56), respectively. Statistical evidence of linkage and association was not shown for study groups other than non-syndromic cleft palate. Neither evidence for parent-of-origin nor maternal genotypic effect was shown for any of the ROR2 markers in our analysis for all study groups.

CONCLUSION

Our results provided evidence of linkage and association between the ROR2 gene and a gene controlling risk to non-syndromic cleft palate.

The FGF and FGFR Gene Family and Risk of Cleft Lip With or Without Cleft Palate

Background : Isolated, nonsyndromic cleft lip with or without cleft palate is a common human congenital malformation with a complex and heterogeneous etiology. Genes coding for fibroblast growth factors and their receptors (FGF/FGFR genes) are excellent candidate genes. Methods : We tested single-nucleotide polymorphic markers in 10 FGF/FGFR genes (including FGFBP1, FGF2, FGF10, FGF18, FGFR1, FGFR2, FGF19, FGF4, FGF3, and FGF9) for genotypic effects, interactions with one another, and with common maternal environmental exposures in 221 Asian and 76 Maryland case-parent trios ascertained through a child with isolated, nonsyndromic cleft lip with or without cleft palate. Results : Both FGFR1 and FGF19 yielded evidence of linkage and association in the transmission disequilibrium test, confirming previous evidence. Haplotypes of three single-nucleotide polymorphisms in FGFR1 were nominally significant among Asian trios. Estimated odds ratios for individual single-nucleotide polymorphic markers and haplotypes of multiple markers in FGF19 ranged from 1.31 to 1.87. We also found suggestive evidence of maternal genotypic effects for markers in FGF2 and FGF10 among Asian trios. Tests for gene-environment (G × E) interaction between markers in FGFR2 and maternal smoking or multivitamin supplementation yielded significant evidence of G × E interaction separately. Tests of gene-gene (G × G) interaction using Cordell's method yielded significant evidence between single-nucleotide polymorphisms in FGF9 and FGF18, which was confirmed in an independent sample of trios from an international consortium. Conclusion : Our results suggest several genes in the FGF/FGFR family may influence risk for isolated, nonsyndromic cleft lip with or without cleft palate through distinct biological mechanisms.

Evidence for gene-environment interaction in a genome wide study of nonsyndromic cleft palate

Nonsyndromic cleft palate (CP) is a common birth defect with a complex and heterogeneous etiology involving both genetic and environmental risk factors. We conducted a genome-wide association study (GWAS) using 550 case-parent trios, ascertained through a CP case collected in an international consortium. Family-based association tests of single nucleotide polymorphisms (SNP) and three common maternal exposures (maternal smoking, alcohol consumption, and multivitamin supplementation) were used in a combined 2 df test for gene (G) and gene-environment (G × E) interaction simultaneously, plus a separate 1 df test for G × E interaction alone. Conditional logistic regression models were used to estimate effects on risk to exposed and unexposed children. While no SNP achieved genome-wide significance when considered alone, markers in several genes attained or approached genome-wide significance when G × E interaction was included. Among these, MLLT3 and SMC2 on chromosome 9 showed multiple SNPs resulting in an increased risk if the mother consumed alcohol during the peri-conceptual period (3 months prior to conception through the first trimester). TBK1 on chr. 12 and ZNF236 on chr. 18 showed multiple SNPs associated with higher risk of CP in the presence of maternal smoking. Additional evidence of reduced risk due to G × E interaction in the presence of multivitamin supplementation was observed for SNPs in BAALC on chr. 8. These results emphasize the need to consider G × E interaction when searching for genes influencing risk to complex and heterogeneous disorders, such as nonsyndromic CP.

Association between genes on chromosome 4p16 and non-syndromic oral clefts in four populations

Isolated cleft lip with or without cleft palate and cleft palate are among the most common human birth defects. Several candidate gene studies on MSX1 have shown significant association between markers in MSX1 and risk of oral clefts, and re-sequencing studies have identified multiple mutations in MSX1 in a small minority of cases, which may account for 1-2% of all isolated oral clefts cases. We explored the 2-Mb region around MSX1, using a marker map of 393 single nucleotide polymorphisms (SNPs) in 297 cleft lip, with or without cleft palate, case-parent trios and 84 cleft palate trios from Maryland, Taiwan, Singapore, and Korea. Both individual markers and haplotypes of two to five SNPs showed several regions yielding statistical evidence for linkage and disequilibrium. Two genes (STK32B and EVC) yielded consistent evidence from cleft lip, with or without cleft palate, trios in all four populations. These two genes plus EVC2 also yielded suggestive evidence for linkage and disequilibrium among cleft palate trios. This analysis suggests that several genes, not just MSX1, in this region may influence risk of oral clefts.

Maternal transmission effects of the PAX genes among cleft case-parent trios from four populations

Isolated cleft lip with or without cleft palate (CL/P) is among the most common human birth defects, with a prevalence of 1 in 700 live births. The paired box (PAX) genes have been suggested as candidate genes for CL/P based largely on mouse models; however, few human studies have focused on this gene family. This study tests for association between markers in four PAX genes and CL/P using a case-parent trio design considering parent-of-origin effects. Trios from four populations (76 from Maryland, 146 from Taiwan, 35 from Singapore, and 40 from Korea) were genotyped for 34 single nucleotide polymorphisms (SNPs) in the PAX3, PAX6, PAX7, and PAX9 genes. We performed the transmission disequilibrium test (TDT) on individual SNPs. Parent-of-origin effects were assessed using the transmission asymmetry test (TAT) and the parent-of-origin likelihood ratio test (PO-LRT). TDT analysis showed one SNP (rs766325) in PAX7 yielding evidence of linkage and association when parent-of-origin was not considered, with an OR(transmission)=1.62 (P=0.003), and five SNPs in PAX6 (including two pairs in near perfect linkage disequilibrium). TAT analysis of all trios revealed two SNPs in PAX7 and four SNPs in PAX3 showing significant excess maternal transmission. For these six SNPs, the maternal OR(transmission) ranged between 1.74 and 2.40, and PO-LRT was also significant (P-values=0.035-0.012). When this analysis was limited to trios with male cases, SNPs in PAX7 showed higher maternal OR(transmission) and greater significance. PAX genes may influence the risk of CL/P through maternal effects, possibly imprinting, which seems to be stronger among male cases.

Differential parental transmission of markers in RUNX2 among cleft case-parent trios from four populations

Isolated cleft lip with or without cleft palate (CL/P) is among the most common human birth defects, with a prevalence around 1 in 700 live births. The Runt-related transcription factor 2 (RUNX2) gene has been suggested as a candidate gene for CL/P based largely on mouse models; however, no human studies have focused on RUNX2 as a risk factor for CL/P. This study examines the association between markers in RUNX2 and isolated, nonsyndromic CL/P using a case-parent trio design, while considering parent-of-origin effects. Case-parent trios from four populations (77 from Maryland, 146 from Taiwan, 35 from Singapore, and 40 from Korea) were genotyped for 24 single nucleotide polymorphisms (SNPs) in the RUNX2 gene. We performed the transmission disequilibrium test on individual SNPs. Parent-of-origin effects were assessed using the transmission asymmetry test and the parent-of-origin likelihood ratio test (PO-LRT). When all trios were combined, the transmission asymmetry test revealed a block of 11 SNPs showing excess maternal transmission significant at the P<0.01 level, plus one SNP (rs1934328) showing excess paternal transmission (P=0.002). For the 11 SNPs showing excess maternal transmission, odds ratios of being transmitted to the case from the mother ranged between 3.00 and 4.00. The parent-of-origin likelihood ratio tests for equality of maternal and paternal transmission were significant for three individual SNPs (rs910586, rs2819861, and rs1934328). Thus, RUNX2 appears to influence risk of CL/P through a parent-of-origin effect with excess maternal transmission.

Excess maternal transmission of markers in TCOF1 among cleft palate case-parent trios from three populations

Isolated cleft palate is among the most common human birth defects. The TCOF1 gene has been suggested as a candidate gene for cleft palate based on animal models. This study tests for association between markers in TCOF1 and isolated, nonsyndromic cleft palate using a case-parent trio design considering parent-of-origin effects. Case-parent trios from three populations (comprising a total of 81 case-parent trios) were genotyped for single nucleotide polymorphisms (SNPs) in the TCOF1 gene. We used the transmission disequilibrium test and the transmission asymmetry test on individual SNPs. When all trios were combined, the odds ratio for transmission of the minor allele, OR(transmission), was significant for SNP rs15251 (OR = 2.88, P = 0.007), as well as rs2255796 and rs2569062 (OR = 2.08, P = 0.03; OR = 2.43, P = 0.041; respectively) when parent of origin was not considered. The transmission asymmetry test also revealed one SNP (rs15251) showing excess maternal transmission significant at the P = 0.005 level (OR = 6.50). Parent-of-origin effects were assessed using the parent-of-origin likelihood ratio test on both SNPs and haplotypes. While the parent-of-origin likelihood ratio test was only marginally significant for this SNP (P = 0.136), analysis of haplotypes of rs2255796 and rs15251 suggested excess maternal transmission. Therefore, these data suggest TCOF1 may influence risk of cleft palate through a parent-of-origin effect.

Identification of IRF6 gene variants in three families with Van der Woude syndrome

Van der Woude syndrome is the most common cause of syndromic orofacial clefting. It is characterised by the presence of lip pits, cleft lip and/or cleft palate. It is transmitted in an autosomal dominant manner, with high penetrance and variable expressivity. Several mutations in the interferon regulatory factor 6 (IRF6) gene have been found in VWS families, suggesting that this gene is the primary locus. We screened for mutations in this gene in three families in our population. There was a recurrent nonsense mutation within exon 9 of the gene for a Malay family consisting of five affected members with different presentations. We also found a co-segregating rare polymorphism which would result in a non-synonymous change 23 bases downstream of the nonsense mutation. This polymorphism was present in <1% of the Malay subjects screened, but was not found among the Chinese and Indians in our population. For another family, a 396C-->T mutation (R45W in the DNA-binding domain) was found in the proband, although the possibility of a genetic defect elsewhere could not be excluded because his mother and twin sister (both unaffected) also had this variant. In the third case with complete absence of family history, a de novo deletion spanning the whole IRF6 gene was detected in the child with VWS. This case of haploinsufficiency caused disruption of orofacial development but not other organ systems as the child has no other medical or developmental abnormalities despite the deletion of at least five other genes.

Association between IRF6 and nonsyndromic cleft lip with or without cleft palate in four populations

PURPOSE

The interferon regulatory factor 6 (IRF6), the gene that causes van der Woude syndrome has been shown to be associated with nonsyndromic cleft lip with or without palate in several populations. This study aimed to confirm the contribution of IRF6 to cleft lip with or without palate risk in additional Asian populations.

METHODS

A set of 13 single nucleotide polymorphisms was tested for association with cleft lip with or without palate in 77 European American, 146 Taiwanese, 34 Singaporean, and 40 Korean case-parent trios using both the transmission disequilibrium test and conditional logistic regression models.

RESULTS

Evidence of linkage and association was observed among all four populations; and two specific haplotypes [GC composed of rs2235373-rs2235371 (p.V274I) and AAG of rs599021-rs2235373-rs595918] showed the most significant over- and undertransmission among Taiwanese cases (P=9x10(-6) and P=5x10(-6), respectively). The AGC/CGC diplotype composed of rs599021-rs2235373-rs2013162 showed almost a 7-fold increase in risk among the Taiwanese sample (P<10(-3)). These results confirmed the contribution of this gene to susceptibility of oral clefts across different populations; however, the specific single nucleotide polymorphisms showing statistical significance differed among ethnic groups.

CONCLUSION

The high-risk genotypes and diplotypes identified here may provide a better understanding of the etiological role of this gene in oral clefts and potential options for genetic counseling.

Analysis of candidate genes on chromosome 2 in oral cleft case-parent trios from three populations

Isolated oral clefts, including cleft lip with/without cleft palate (CL/P) and cleft palate (CP), have a complex and heterogeneous etiology. Case-parent trios from three populations were used to study genes spanning chromosome 2, where single nucleotide polymorphic (SNP) markers were analyzed individually and as haplotypes. Case-parent trios from three populations (74 from Maryland, 64 from Singapore and 95 from Taiwan) were genotyped for 962 SNPs in 104 genes on chromosome 2, including two well-recognized candidate genes: TGFA and SATB2. Individual SNPs and haplotypes (in sliding windows of 2-5 SNPs) were used to test for linkage and disequilibrium separately in CL/P and CP trios. A novel candidate gene (ZNF533) showed consistent evidence of linkage and disequilibrium in all three populations for both CL/P and CP. SNPs in key regions of ZNF533 showed considerable variability in estimated genotypic odds ratios and their significance, suggesting allelic heterogeneity. Haplotype frequencies for regions of ZNF533 were estimated and used to partition genetic variance into among-and within-population components. Wright's fixation index, a measure of genetic diversity, showed little difference between Singapore and Taiwan compared with Maryland. The tensin-1 gene (TNS1) also showed evidence of linkage and disequilibrium among both CL/P and CP trios in all three populations, albeit at a lower level of significance. Additional genes (VAX2, GLI2, ZHFX1B on 2p; WNT6-WNT10A and COL4A3-COL4A4 on 2q) showed consistent evidence of linkage and disequilibrium only among CL/P trios in all three populations, and TGFA showed significant evidence in two of three populations.

[Endoscopically assisted Le Fort 1 osteotomy: a study in human cadaver heads]

METHODS AND RESULTS

Endoscopically assisted Le Fort 1-osteotomy was performed in a cadaver study with six human skulls. Vertical incisions were used to approach the maxilla using the endoscope. The bone cuts could be carried out with a 4-mm osteotome preserving the buccal mucosa. The downfracture of the maxilla was accomplished without damaging the descending palatal arteries, which could be verified endoscopically. Rigid fixation was performed using 1.5-mm titanium plates (Synthes, Mathys AG, Bettlach, Switzerland) and self-drilling screws.

DISCUSSION

This cadaver study showed that the Le Fort 1 osteotomy could be carried out through limited approaches using endoscopic techniques and self-drilling fixation tools. Further experimental work and improvements will help to introduce this technique into clinical application.

[Individually CAD-CAM technique designed, bioresorbable 3-dimensional polycaprolactone framework for experimental reconstruction of craniofacial defects in the pig]

METHODS

Twenty orbital defects (2 x 2 cm) were created in ten adult Yorkshire pigs. Two software products (Velocity and Mimix) were evaluated with regard to image processing, three-dimensional reconstruction, and fabrication of individually shaped polycaprolactone (PCL) scaffolds to reconstruct these defects. Four different techniques were tested for the reconstruction: group 1 = no reconstruction, group 2 = polylactide sheet, group 3 = PCL scaffold, group 4 = bone marrow-coated PCL scaffold. The pigs were sacrificed at 3 months.

RESULTS

In group 1 soft tissue scar formation could be found, but without any new bone. Group 2 showed a thick fibrous capsule around the PLLA sheet, whereas at the border zone of the defect signs of new bone formation could be detected. In group 3 the PCL scaffolds were filled with fibrous tissue and some areas that showed new bone formation (6.4% of the area of the defect). In group 4 the new bone formation (17.8% of the area of the defect) was significantly higher in quantity than in group 3.

CONCLUSION

The PCL scaffold coated with bone marrow seems to be a material that effectively provides osteoinduction with formation of new bone. Long-term results at 12 months are still pending.

Repair of composite zygomatico-maxillary defects with free bone grafts and free vascularized tissue transfer

INTRODUCTION

Three-dimensional repair of the zygomatico-maxillary defect calls for an elaborate technique to achieve facial symmetry and correct globe position. We present a technique, which combines the use of a free vascularized soft tissue flap and free bone grafts for repair of composite zygomatico-maxillary defects.

PATIENTS

Three patients that underwent radical resection of the maxilla and the zygoma have undergone facial reconstruction using this technique. The mean follow up was 9 months.

METHODS

The key points of this technique are: (1) precise reconstruction of the zygomatico-maxillary complex including the orbit; (2) creation of a skeletal framework for canthopexy and suspension of the free flap; (3) repair of through-and-through soft tissue defects with a folded musculocutaneous free flap; and (4) simultaneous harvesting and reconstruction using two surgical teams to reduce the duration of surgery.

RESULTS

Reconstruction of the zygomatico-maxillary complex could be successfully accomplished in a single surgical procedure.

CONCLUSION

This paper presents a method of repairing zygomatico-maxillary defects with free bone grafts and vascularized soft tissue. However, this concept has yet to be reviewed in the long term.

Endoscopically assisted Le Fort I osteotomy

OBJECTIVES

A new technique of the Le Fort I osteotomy using endoscopic techniques through limited approaches has been evaluated.

PATIENTS

This technique was first carried out successfully in a study on six cadavers. Thereafter we performed endoscopically assisted Le Fort l osteotomy in two patients.

METHODS

Four vertical incisions were used in the vestibule (paranasally and posteriorly) as approaches. The endoscope allowed direct visualization of the osteotomy of the maxilla including the pterygomaxillary junction. The osteotomies could be accomplished with a straight 4 mm osteotome for medial and lateral antral walls and nasal septum and a curved osteotome for the pterygomaxillary junction.

RESULTS

The procedures were successful. The descending palatal arteries could be preserved in all cases as a result of endoscopic control. Rigid fixation of the downfractured maxillae was carried out using self-drilling titanium screws and plates.

CONCLUSION

Endoscopic visualization allowed safe osteotomy of the medial antral wall preserving the descending palatal artery in all cases and hence less bleeding. Postoperative oedema and swelling in the two clinical cases was definitely reduced when compared with the conventional technique. The time needed for these first two clinical cases was approximately 1 h 30 min, i.e., about 30 min more than with the open technique. Further experience and experimental work, and refinements in technique will help to improve this procedure in its clinical application.

Establishment of animal models using experimental rats for allogeneic tissue transplantation and quantitative flow cytometric detection of immunochimera

Establishment of animal models used for allogeneic tissue transplantation, MHC phenotyping as well as quantitative detection of immunochimera were carried out in this study. Both Buffalo (BUF) and Lewis (LEW) rats were chosen as the target animals. The rats were treated with single dose cyclophosphamide (Cy) of 25 to 100 mg/kg to mimic the standard conditioning therapy. Total white blood cells (WBC) were monitored daily for up to 8 days: WBC reached the nadir by day 4 and started to recover by day 5 with an obvious rebounce at day 7 of Cy treatment. Flow cytometric techniques were used to determine the haplotypes of the major histocompatibility complex (MHC) as well as quantitative detection of immunochimerism in unfractionated rat WBC. Monoclonal antibodies against the rat class-I MHC antigens RT1Aab and RT1Au were used to label the class-I MHC antigens on total rat WBC. The results showed that the BUF rats were positive for both RT1Aab and RT1Au antigens, whilst the LEW rats were negative for both. Immunochimera was mimicked in vitro by serial dilution, ranging from 1/1 to 1/10(5) of (BUF/LEW) WBC. A sensitivity of 1/10(4) (BUF/LEW WBC) was achieved. The results showed that there were at least 2 major MHC mismatched loci between BUF and LEW rats and flow cytometry provided a sensitive method for the detection of immunochimera in unfractionated rat WBC. We concluded from this study that both strains of rats could be used as models for allogeneic tissue transplantation across at least two major MHC-mismatches. The sensitivity of flow cytometric method was satisfactory for the detection of immunochimera.

Ecthyma gangrenosum in a patient with hypogammaglobulinemia

Ecthyma gangrenosum is a characteristic skin lesion that is caused by Pseudomonas aeruginosa (P. aeruginosa) in the majority of cases. Systemic P. aeruginosa usually complicates debilitating conditions like leukaemia, burns and cystic fibrosis. We report a patient with underlying hypogammaglobulinemia who developed ecthyma gangrenosum secondary to P. aeruginosa septicaemia, which was potentially life-threatening. Recognition of the characteristic skin lesions with prompt initiation of appropriate antibiotics and intravenous immunoglobulins were life-saving. A review of the English literature reports three other cases of ecthyma gangrenosum in patients with underlying hypogammaglobulinemia.