Candidate Genes for Nonsyndromic Cleft Palate Detected by Exome Sequencing

Nonsyndromic cleft palate only (nsCPO) is a facial malformation that has a livebirth prevalence of 1 in 2,500. Research suggests that the etiology of nsCPO is multifactorial, with a clear genetic component. To date, genome-wide association studies have identified only 1 conclusive common variant for nsCPO, that is, a missense variant in the gene grainyhead-like-3 ( GRHL3). Thus, the underlying genetic causes of nsCPO remain largely unknown. The present study aimed at identifying rare variants that might contribute to nsCPO risk, via whole-exome sequencing (WES), in multiply affected Central European nsCPO pedigrees. WES was performed in 2 affected first-degree relatives from each family. Variants shared between both individuals were analyzed for their potential deleterious nature and a low frequency in the general population. Genes carrying promising variants were annotated for 1) reported associations with facial development, 2) multiple occurrence of variants, and 3) expression in mouse embryonic palatal shelves. This strategy resulted in the identification of a set of 26 candidate genes that were resequenced in 132 independent nsCPO cases and 623 independent controls of 2 different ethnicities, using molecular inversion probes. No rare loss-of-function mutation was identified in either WES or resequencing step. However, we identified 2 or more missense variants predicted to be deleterious in each of 3 genes ( ACACB, PTPRS, MIB1) in individuals from independent families. In addition, the analyses identified a novel variant in GRHL3 in 1 patient and a variant in CREBBP in 2 siblings. Both genes underlie different syndromic forms of CPO. A plausible hypothesis is that the apparently nonsyndromic clefts in these 3 patients might represent hypomorphic forms of the respective syndromes. In summary, the present study identified rare variants that might contribute to nsCPO risk and suggests candidate genes for further investigation.

A new method of monitoring osteomyelitis

Chronic infections of bone such as osteomyelitis are frequent events, especially in immunocompromised or diabetic patients, and costly on a national level. Incorrect treatment or delayed diagnosis may lead to loss of the affected extremity or mandible. The aim of this study was to assess the possible value of urinary lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP) concentrations in the monitoring of mandibular osteomyelitis. Patients were assigned to the following groups: group 1 (n=85), control; group 2a (n=38), patients with active disease; group 2b (n=25), patients of group 2a 6 months after successful treatment; group 2c (n=7), patients of group 2a with ongoing osteomyelitis 6 months after treatment. The range and upper limit of normal values (HP(max) and LP(max)) were determined in group 1. Levels of LP and HP were measured by high-performance liquid chromatography and fluorescence detection. There was a significant decrease (mean 45.43% for HP and 32.12% for LP) in samples of group 2b compared to 2a (P<0.001 for HP and LP). There was a significant increase in HP values in samples from group 2c compared to 2a (P=0.018). The urinary concentrations of HP and LP appear to act as a marker of disease activity, with a decrease reflecting treatment success and an increase or stable values indicating persistent disease. An inexpensive tool (US$5 per analysis) for the monitoring of osteomyelitis is described.

Human beta-defensin (hBD-1, -2) expression in dental pulp

The purpose of this study was to investigate the expression of human beta-defensins (hBD-1, -2) in dental pulps by reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. The mRNA transcripts of human beta-defensin-1 and human beta-defensin-2 could be detected by performing RT-PCR. With immunohistochemical staining of pulp tissue using antisera to hBD-1 and -2 it was possible to demonstrate cytoplasmic expression in odontoblasts. The results demonstrate that not only oral keratinocytes at the epithelial surface but also odontoblasts express human beta-defensins. Thus odontoblasts take part in the innate immune system and human beta-defensins may play an important role in the innate host defense of human dental pulp.

Differential gene expression of human beta-defensins (hBD-1, -2, -3) in inflammatory gingival diseases

Antimicrobial peptides, like human beta-defensins, play an important role in the epithelial innate defense response. The aim of the present study was to investigate the quantitative expression of human beta-defensin-1, -2, and -3 in inflammatory gingival diseases. Gingival biopsies were obtained from patients with healthy gingiva (n = 10), patients with gingivitis (n = 10), and patients with periodontitis (n = 10). The clinical diagnosis was verified by histology. Gingival tissues were used for RNA extraction followed by reverse transcription. Gene expression was quantified by real-time polymerase chain reaction (normalization with GAP-DH). Comparing the tissues with different clinical stages of health and disease, no significant differences in mRNA expression were found for any of the beta-defensins studied. Similar levels of expression were found in healthy gingiva, whereas in gingivitis samples there was a significantly higher expression of hBD-2 compared to hBD-1 (P = 0.004) and hBD-3 (P = 0.016). Likewise, in periodontitis samples, hBD-2 expression was significantly higher than hBD-1 (P = 0.016); however, hBD-2 expression was comparable to hBD-3. In conclusion, the results of the present study showed a differential expression of human beta-defensins (hBD-1, -2, -3) in tissues with inflammatory gingival disease.

Follow-up of collagen crosslink excretion in patients with oral squamous cell carcinoma and analysis of tissue samples

The presence of an oral squamous cell carcinoma (OSCC) may be associated with increased urinary excretion of the markers of collagen degradation, hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP). We investigated the possibility of these markers predicting the presence of active disease. Patients from a current study on HP and LP were included as follows: Group 1a (OSCC with confirmed mandibular bony infiltration, n=12), group 1b (group 1a patients >6 months after successful treatment), group 2a (OSCC without evidence of mandibular bone infiltration, n=8), group 2b (group 2a patients >6 months after successful treatment), group 3a (recurrent OSCC, n=8), group 3b (group 3a patients >6 weeks later, symptoms unchanged) and group 4 (control group, n=74). Tissue samples from tumour tissue and adjacent healthy mucosa were additionally investigated for HP and LP concentrations (n=8). The decrease in the urinary concentrations of HP and LP was statistically significant between groups 1a and 1b (P<0.001 for HP and LP), but not between groups 2a and 2b (P=0.07 for HP and LP), while values in groups 1b and 2b were within the normal range. When comparing groups 3a and 3b, a significant increase was observed for LP (P=0.050), but not HP (P=0.208). In conclusion, successful treatment of OSCC with bony involvement may be associated with a reduction of urinary HP and LP, whereas ongoing disease may result in an increase of LP. HP and LP may both be useful markers of tumour progression in patients with OSCC.

Collagen crosslink excretion and staging of oral cancer

Lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP) are collagen crosslink residues of which the urinary concentration reflects the level of connective-tissue turnover. HP is ubiquitous in tissue, whereas LP is specific for bone. The purpose of this investigation was to assess the sensitivity and specificity of an increased urinary concentration of both HP and LP in indicating infiltration of mandibular bone by an oral squamous cell carcinoma (OSCC) or recurrence of the disease after successful therapy. We investigated the history and urine levels in 116 adult patients, who were divided into the following groups. Group 1: patients with OSCC with bone infiltration (n=17); group 2: patients with confirmed OSCC (n=12) without evidence of bone infiltration; group 3: patients with recurrence of an OSCC (n=13); group 4: patients without clinical evidence of disease (n=74). The range and upper limit of normal values (HP(max) and LP(max)) were measured from the normal controls in group 4. Levels of LP and HP were measured by HPLC and fluorescence detection. There was a significant difference in the average urinary levels of LP and HP between groups 1-4 (P<0.001). The presence of mandibular bone infiltration could be detected with a sensitivity and specificity of 100% when comparing groups 1 and 2. Presence of tumour tissue could be detected with a sensitivity of 90%. In conclusion, a normal LP concentration in patients with an OSCC strongly suggests that bone invasion by the disease has not taken place. If both urinary HP and LP are elevated, disease recurrence is highly likely.

Lichenoid reactions of murine mucosa associated with amalgam

BACKGROUND

In 97% of all patients with oral lichenoid reactions (OLR) associated with dental amalgam a removal of the fillings leads to a decline of the lesions, as a minimum.

OBJECTIVES

The aim of this study was to determine if contact allergic or local toxic effects or both may contribute to OLR using an animal model with mercury-sensitive and non-sensitive rats.

METHODS

Twenty Brown Norway rats, which have a genetic predisposition for an autoimmune syndrome after exposure to mercury and 20 Lewis rats, not mercury sensitive, were treated as follows: 10 animals of each group were sensitized with a low dose of mercuric chloride. Half of all animals received local exposure of the right buccal mucosa to amalgam (left: control), the others to amalgam alloy free of mercury. All rats were patch tested with an amalgam series.

RESULTS

After 20 days of exposure 96% of all animals showed white mucosal lesions restricted to the contact zone of the alloy on the treated side, but only up to 25% had a positive patch test reaction to amalgam or inorganic mercury (INM). The lesions showed no relation to species, alloy, sensitization or patch test reaction.

CONCLUSIONS

While allergic mechanisms may contribute to mucosal contact lesions in Brown Norway rats, this is less probable in Lewis rats. Mercury in general appears to be irrelevant in the development of ORL in this study. If this holds true for humans as well, patch testing with an amalgam series may be helpful in a minor fraction of all patients with OLR.

Oral lichenoid reactions associated with amalgam: improvement after amalgam removal

BACKGROUND

The pathogenetic relationship between oral lichenoid reactions (OLR) and dental amalgam fillings is still a matter of controversy.

OBJECTIVES

To determine the diagnostic value of patch tests with amalgam and inorganic mercury (INM) and the effect of amalgam removal in OLR associated with amalgam fillings.

METHODS

In 134 consecutive patients 467 OLR were classified according to clinical criteria. One hundred and fifty-nine biopsies from OLR lesions were histologically diagnosed according to the World Health Organization criteria for oral lichen planus (OLP) and compared with 47 OLP lesions from edentulous patients without amalgam exposure. One hundred and nineteen patients were patch tested with an amalgam series. In 105 patients (357 of 467 lesions) the amalgam fillings were removed regardless of the patch test results and OLR were re-examined within a follow-up period of about 3 years. Twenty-nine patients refused amalgam removal and were taken as a control group.

RESULTS

Eleven patients with OLR (8.2%) had skin lesions of lichen planus (LP). Histologically, the lesions in the OLR group could not be distinguished from those seen in the OLP group. Thirty-three patients (27.7%) showed a positive patch test to INM or amalgam. Amalgam removal led to benefit in 102 of 105 patients (97.1%), of whom 31 (29.5%) were cured completely. Of 357 lesions, 213 (59.7%) cleared after removal of amalgam, whereas 65 (18.2%) did not improve. In the control group without amalgam removal (n = 29) only two patients (6.9%) showed an improvement (P < 0.05). Amalgam removal had the strongest impact on lesions of the tongue compared with lesions at other sites (P < 0.05), but had very little impact on intraoral lesions in patients with cutaneous LP compared with patients without cutaneous lesions (P < 0.05). Patients with a positive patch test reaction to amalgam showed complete healing more frequently than the amalgam-negative group (P < 0.05). After an initial cure following amalgam removal, 13 lesions (3.6%) in eight patients (7.6%) recurred after a mean of 14.6 months.

CONCLUSIONS

Of all patients with OLR associated with dental amalgam fillings, 97.1% benefited from amalgam removal regardless of patch test results with amalgam or INM. We suggest that the removal of amalgam fillings can be recommended in all patients with symptomatic OLR associated with amalgam fillings if no cutaneous LP is present.

[Comparison of secondary and tertiary cleft jaw osteoplasty. 20 year analysis]

BACKGROUND

The aim of secondary cleft osteoplasty is to provide alveolar bone for the complete eruption of the canine and sometimes of the lateral incisor to the occlusal plane and, thus, preservation of a continuous dental arch. This concept has not changed during the last 20 years in our clinic, providing an opportunity for an analysis of a homogeneous group of cleft patients. This group of patients was compared with a similar group of tertiary osteoplasties, performed during the same time span in our clinic.

MATERIAL AND METHODS

From 1980 to 1999, 376 cleft osteoplasties were performed in 295 patients, 264 of whom (136 secondary and 128 tertiary osteoplasties) were available for continuous prospective follow-up. Special emphasis was put on preoperative orthodontic treatment with removal of crossbites, oral hygiene, and meticulous disinfection. Autogenous cancellous iliac bone was used exclusively.

RESULTS

The postoperative height of the interalveolar septum (Abyholm classes) was I (1/1, 69.4%/45.8%), II (> 3/4, 28.2%/41.7%), III (< 3/4, 2.4%/10%), and IV (complete failure, 0%/2.5%) (secondary vs tertiary). Complications were infections (6.6% vs 14%), fistulae (0.7% vs 5.8%), and external root resorption (0% vs 7.4%). The lateral incisor was aligned into the arch in 55.5% vs 29.8% and the canine was in the correct position in 100% vs 83.6% (secondary vs tertiary).

CONCLUSION

Secondary cleft osteoplasty was more advantageous than tertiary due to better preservation of the neighboring teeth.

[Development of speech and facial skull growth after primary velopharyngoplasty in lip-jaw-palate clefts]

BACKGROUND

A two-armed, prospective, randomized study was performed to evaluate the influence of primary velopharyngoplasty on speech and facial growth in patients with cleft lip and palate.

PATIENTS AND METHODS

Forty-two patients born between 1978 and 1982 were included. All patients were treated with an intravelar veloplasty, and 21 patients simultaneously with a velopharyngoplasty according to Sanvenero-Rosselli. The patients were examined at the age of 5, 10, 15, and 18 years according to the recommendations of the research group of the German Association of Craniomaxillofacial Surgery for minimal documentation.

RESULTS

Patients treated with primary velopharyngoplasty showed a higher deficit in transversal growth of the maxilla of 0.6 mm in the molar region in adolescence in comparison to the control group. The sagittal growth of the maxilla was reduced at 2.6 degrees in the SNA angle. A statistically significant decrease in growth of the maxilla caused by primary velopharyngoplasty was not detectable (p > 0.05). The incidence of rhinophonia and dyslalia did not differ significantly. Primary velopharyngoplasty did not lead to speech improvement either in childhood or in adolescence.

CONCLUSION

With regard to a potential decrease in growth of the maxilla and the disadvantages of a hindered nasal respiration, a primary velopharyngoplasty therefore does not seem to be indicated.

Mandibular reconstruction with prefabricated vascularized bone grafts using recombinant human osteogenic protein-1: an experimental study in miniature pigs. Part II: transplantation

Osteogenic Protein-1 (rhOP-1), also called bone morphogenetic protein-7 (BMP-7), is osteoinductive. The aim of this study was to present a new surgical technique: the prefabrication of a vascularized bone graft using rhOP-1 and its microsurgical transplantation. During 6 weeks, osteomuscular grafts were prefabricated in the latissimus dorsi muscle of five adult minipigs. Six hundred micrograms rhOP-1 on a carrier of xenogenic bone mineral in block form were used. The grafts were transplanted into defects of the mandibular angles performing a microsurgical anastomosis and using miniplates for fixation. Identical defects of the contralateral side were treated by direct application of 600 microg rhOP-1 and xenogenic bone mineral. A polychrome sequential labelling was applied. After transplantation the bone stayed viable, demonstrated by continuous apposition of fluorochromes (non-decalcified histologic sections) and bone scintigraphy. The reconstructive result was significantly superior in the prefabrication technique, assessed by histology and computerized tomography (CT). In conclusion, the method has a potential to become a clinical alternative for conventional vascularized bone grafts.

[Congenital cerebriform nevus cell nevus on the occiput. Removal after tissue expander implantation]

A 26 year old man presented with a giant cerebriform nevus on the occiput. Clinical appearance of the nevus, maceration within the folding and risk of malignancy prompted us to perform a complete excision. The scalp defect was closed with a rotation flap following an implantation of a tissue expander.

Acne with chronic recurrent multifocal osteomyelitis involving the mandible as part of the SAPHO syndrome: case report

For 12 years, a 26-year-old man had acne conglobata and a non-suppurative diffuse sclerosing osteomyelitis of the mandible as part of a chronic recurrent multifocal osteomyelitis of the sternum, the pelvic bones, and the femoral head, and aseptic arthritis of the knee, the fibulotalar, and the sternoclavicular joints. This fulfills the formal criteria of the SAPHO syndrome. Repeated surgical and antibiotic treatment combined with hyperbaric oxygen caused partial improvement. Complete relief and partial disappearance of the scintigraphic lesions was achieved with long-term corticosteroids, non-steroidal anti-inflammatory drugs, minocycline, and isotretinoin.

Expression profile of human defensins and antimicrobial proteins in oral tissues

Antimicrobial peptides and proteins are an important part of the innate host defense. In the present study, the expression profile of three human alpha-defensins, of two human beta-defensins (hBD) and of phospholipase A-2 (PLA-2) and lysozyme was determined by reverse transcription-polymerase chain reaction (RT-PCR) in 56 non-inflamed and 18 inflamed oral tissue samples and primary oral keratinocytes and fibroblasts. The transcripts for hBD-1 and -2 as well as for PLA-2 and lysozyme were found to be widely expressed. In the group of the alpha-defensins, the message for the human neutrophil peptide-1 (HNP-1) was frequently detected, whereas an expression of human Paneth's cell defensin-5 (HD-5) was identified in only a minority of samples. Transcripts for HD-6 were not detectable in any sample. Oral keratinocytes but not fibroblasts contained transcripts for the beta-defensins, suggesting that these defensins are produced in the epithelial compartment. In contrast, mRNA expression of neutrophil-derived HNP-1 and PLA-2 was not observed in any of these cells. These results suggest an important role for hBD-1 and hBD-2 in the innate oral epithelial host defense.

Three-dimensional cultivation of human osteoblast-like cells on highly porous natural bone mineral

In this study, we investigated the growth and extracellular matrix synthesis of human osteoblast-like cells on highly porous natural bone mineral. Human bone cells were isolated from trabecular bone during routine iliac crest biopsies. Under conventional culture conditions, trabecular bone cells were able to assume the organization of a three-dimensional structure on a porous natural bone mineral (Bio-Oss(R) Block). Scanning electron microscopy examination after 6 weeks revealed multiple cell layers on the trabecular block. Transmission electron microscopy examination after 6 weeks revealed the accumulation of mature collagen fibrils in the intracellular and extracellular spaces, and showed multilayered, rough endoplasmic reticulum as well as mitochondria-rich cells surrounded by dense extracellular matrix. These morphological observations suggest that the cell layer may resemble the natural three-dimensional structure. Biochemical analysis revealed that the hydroxylysylpyridinoline, lysylpyridinoline, and hydroxyproline content of the cell layer increased in a time-dependent manner, whereas in monolayer culture without natural bone mineral, no measurable amounts of hydroxylysylpyridinoline or lysylpyridinoline, and a barely measurable amount of hydroxyproline, were noted. Mature collagen extracted by ethylenediaminetetraacetic acid-demineralization from the cell layer on natural bone mineral showed an identical electrophoretic pattern to that observed in human bone, as evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The present study demonstrated an excellent biocompatibility of the highly porous natural bone mineral in a three-dimensional bone cell culture system, and thus its potential for tissue-engineered growth of human bone.

[Precancer stages of the oral mucosa: a review]

According to the WHO collaborating centre precancerous lesions and precancerous conditions have to be distinguished. Precancer:

BACKGROUND

Erythroplakia is the most dangerous precancerous lesion. It is rare, but may often remain undetected. It will transform into cancer within five years and therefore, has to be excised in every case. Leukoplakias show malignant transformation in 3-45% of the cases. In spite of modern molecular biological and immunohistochemical techniques the clinical appearance and the histological grading of the dysplasia are still most important prognostic factors. Until 1992 every lesion showing signs of moderate and severe dysplasia was excised in our department. Despite this treatment strategy 6.2% of the leukoplakias (n = 161) transformed into cancer. Therefore, we recommend to remove every lesion which does not disappear after eliminating the etiological factors.

METHODS

Since 1992 168 leukoplakias were completely removed using the CO2 Laser and underwent histological examination.

RESULTS

In 3% of these cases a carcinoma was detected in the leukoplakia; 5% of the lesions recurred. Precancerous condition: The most important precancerous condition, the oral lichen planus is treated in cases of erosive lesions only or if the patient is suffering from the symptoms. Malignant transformation is seen in 1.5% of the patients within 10 to 15 years. Histologically the oral lichen planus does not differ from the oral lichenoid reactions, lesions in contact with amalgam restorations mostly. In these cases a causative treatment with replacement of the amalgam is recommended.

[Significance of vascularization of jejunal transplants in secondary reconstruction of the mandible]

There is a difference in the vascular architecture of myocutaneous flaps and jejunal free flaps both available to replace resected mucosal tissue of the oral cavity after surgical treatment of oral cancer. The question in whether the mobilization of jejunal free flaps is possible without respect to the anastomized vessels in particular in secondary reconstruction procedures to achieve a bony continuity of the mandible. From 1985-1992 22 patients were operated on using microsurgically anastomized jejunal free flaps. In 7 cases a secondary mandibular reconstruction by means of microsurgically anastomized iliac crest grafts was performed. In respect of our results we recommend in cases of secondary mandibular reconstruction with mobilisation of the jejunal flap. 1. preoperative digital subtraction angiography, 2. temporary clamp of anastomized vessels with observation of the perfusion of the jejunal flap, 3. intraoperative doppler-sonography. These techniques allow a save evaluation of the vessels of the donor site prior to microvascular anastomoses for secondary bony reconstruction of the mandible.