Craniofacial and dental findings in cystinosis.

OBJECTIVES: Cystinosis is a rare autosomal recessive lysosomal storage disorder with developmental and mineralization anomalies as part of its clinical presentation. The objective of this study was to provide the first systematic assessment of the craniofacial and dental characteristics associated with cystinosis. STUDY DESIGN: Oral and radiographic evaluations were performed on 73 patients with cystinosis. Analyses of cephalometry (n = 20), taurodontism (n = 47), caries (n = 47), enamel defects (n = 48), soft tissue anomalies (n = 48), and dental age (n = 41) were performed on the cystinosis group, and compared with age- and sex-comparable controls or standards. RESULTS: Cystinosis patients manifested relative mandibular deficiency, an increased facial height, and a reduced airway space. Taurodontism and enamel defects were significantly more prevalent in cystinosis patients compared with controls (P < 0.0001 and P = 0.027, respectively). Children (aged <15 years) with cystinosis also demonstrated a significant delay, of almost 9 months, of their dental development (P < 0.001). CONCLUSION: Novel craniofacial and dental features are associated with cystinosis. Craniofacial deficiencies may influence the swallowing and respiratory complications seen in cystinosis. Renal pathology and associated mineral imbalance may explain the dental root and enamel anomalies found in cystinosis patients; the developmental delays in cystinosis include delayed dental formation.

Hyper IgE (Job's) syndrome: a primary immune deficiency with oral manifestations.

Autosomal dominant hyper IgE (HIES or Job's) syndrome is a rare primary immune deficiency characterized by eczema, recurrent skin and lung infections, extremely elevated serum IgE, and a variety of connective tissue and skeletal abnormalities. Individuals with HIES share a characteristic facial appearance and many oral manifestations including retained primary dentition, a high arched palate, variations of the oral mucosa and gingiva, and recurrent oral candidiasis. Mutations in STAT3 account for the majority, if not all, of the cases of autosomal dominant HIES, but the pathogenesis of the many varied features remains poorly understood. In this review, we discuss the clinical phenotype of HIES including immunologic and non-immunologic features, the genetics of HIES, and treatment.

Hutchinson-Gilford progeria syndrome: oral and craniofacial phenotypes.

OBJECTIVE: Hutchinson-Gilford progeria syndrome (HGPS) is a rare early-onset accelerated senescence syndrome. In HGPS, a recently identified de novo dominant mutation of the lamin A gene (LMNA) produces abnormal lamin A, resulting in compromised nuclear membrane integrity. Clinical features include sclerotic skin, cardiovascular and bone abnormalities, and marked growth retardation. Craniofacial features include 'bird-like' facies, alopecia, craniofacial disproportion, and dental crowding. Our prospective study describes dental, oral soft tissue, and craniofacial bone features in HGPS. METHODS: Fifteen patients with confirmed p.G608G LMNA mutation (1-17 years, seven males, eight females) received comprehensive oral evaluations. Anomalies of oral soft tissue, gnathic bones, and dentition were identified. RESULTS: Radiographic findings included hypodontia (n = 7), dysmorphic teeth (n = 5), steep mandibular angles (n = 11), and thin basal bone (n = 11). Soft tissue findings included ogival palatal arch (n = 8), median sagittal palatal fissure (n = 7), and ankyloglossia (n = 7). Calculated dental ages (9 months to 11 years 2 months) were significantly lower than chronological ages (1 year 6 months to 17 years 8 months) (P = 0.002). Eleven children manifested a shorter mandibular body, anterior/posterior cranial base and ramus, but a larger gonial angle, compared to age/gender/race norms. CONCLUSION: Novel oral-craniofacial phenotypes and quantification of previously reported features are presented. Our findings expand the HGPS phenotype and provide additional insight into the complex pathogenesis of HGPS.

Enamel defects and salivary methylmalonate in methylmalonic acidemia.

INTRODUCTION AND OBJECTIVE: To characterize enamel defects in patients with methylmalonic acidemia (MMA) and cobalamin (cbl) metabolic disorders and to examine salivary methylmalonate levels in MMA. SUBJECTS AND METHODS: Teeth from patients (n = 32) were evaluated for enamel defects and compared with age- and gender-matched controls (n = 55). Complementation class (mut, cblA, cblB and cblC) and serum methylmalonate levels were examined. Primary teeth from two patients were examined by light and scanning electron microscopy and salivary methylmalonate levels from two patients were analyzed. RESULTS: Enamel defects were significantly more prevalent per tooth in the affected group than the control group, across complementation types (P < 0.0001). The mut MMA subgroup had a significantly higher prevalence per individual of severe enamel defects than controls (P = 0.021), and those with enamel defects exhibited higher serum methylmalonate levels than those without (P = 0.017). Salivary methylmalonate levels were extremely elevated and were significantly higher than controls (P = 0.002). Primary teeth were free of enamel defects except for two cblC patients who exhibited severe enamel hypoplasia. One primary tooth from a cblC patient manifested markedly altered crystal microstructure. CONCLUSION: Enamel anomalies represent a phenotypic manifestation of MMA and cbl metabolic disorders. These findings suggest an association between enamel developmental pathology and disordered metabolism.

Novel intraoral phenotypes in hyperimmunoglobulin-E syndrome.

AIM: Hyperimmunoglobulin-E syndrome (HIES) is a primary immunodeficiency characterized by eczema, recurrent skin and lung infections with pneumatocoele formation, and extremely elevated serum immunoglobulin-E. The precise immunologic defect and genetic etiology remain unknown. Non-immunologic findings include characteristic facial features (prominent forehead, fleshy nasal tip, and increased interalar distance); skeletal involvement (pathological fractures, scoliosis, and craniosynostosis); and retention of primary teeth. This study aims to characterize intraoral soft tissue findings in HIES patients. METHODS: Sixty HIES patients (4-54 years, 27 males, 33 females) received intraoral and radiographic evaluations. Chronological dental development was also assessed. RESULTS: Lesions of the hard palate and dorsal tongue were found in 55% and 60% of patients, respectively. Palatal lesions ranged from a generalized surface keratosis to a midline sagittal fibrotic bridge. Tongue lesions consisted of multiple fissures and a midline cleft. On the lip and buccal mucosa, keratotic plaques and/or surface fissures were found in 8% and 23% of patients, respectively. Manifested in 76.7% of patients, the intraoral lesions were significantly more prevalent than the characteristic facial traits (P=0.0013). CONCLUSIONS: Alterations in oral mucosa and gingiva were present in the majority of HIES patients. These novel intraoral findings may facilitate the diagnosis of HIES.

Oral and dental phenotype of dyskeratosis congenita.

Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome that is characterized by lacey reticular hyperpigmentation of the skin, dystrophic nails, mucous membrane leukoplakia and pancytopenia. Diagnosis may be delayed until clinical signs are apparent. Severe pancytopenia frequently causes early mortality of DC patients, who have an increased risk of developing oropharyngeal squamous cell carcinoma. Several case reports have described oral changes in DC, which include oral leukoplakia, increased dental caries, hypodontia, thin enamel structure, aggressive periodontitis, intraoral brown pigmentation, tooth loss, taurodontism and blunted roots. We determined the prevalence of these previously reported findings in a cohort of 17 patients with DC and 23 family members. The most common oral changes in DC patients were oral leukoplakia (65% of the entire DC population), decreased root/crown ratio (75% with sufficient tooth development) and mild taurodontism (57% with sufficient tooth development). From the clinical perspective, a diagnosis of DC or other inherited bone marrow failure syndrome should be considered in young persons with oral leukoplakia, particularly those with no history of smoking. Multiple permanent teeth with decreased root/crown ratios further suggest DC.

Characterization of the human transferrin receptor produced in a baculovirus expression system.

Recombinant human transferrin receptor has been produced in a baculovirus expression system. Magnetic particles coated with an anti-transferrin receptor monoclonal antibody were used to immunoselect virus-infected Sf9 insect cells expressing the human transferrin receptor on their cell surface. Recombinant virus containing the human transferrin receptor cDNA was then plaque-purified from these cells. Biosynthetic labeling studies of infected cells showed that the human transferrin receptor is one of the major proteins made 2-3 days postinfection. The recombinant receptor made in insect cells is glycosylated and is also posttranslationally modified by the addition of a fatty acid moiety. However, studies with tunicamycin and endoglycosidases H and F showed that the oligosaccharides displayed on the recombinant receptor differ from those found on the naturally occurring receptor in human cells. As a consequence, the human receptor produced in the baculovirus system has an Mr of 82,000 and is smaller in size than the authentic receptor. About 30% of human transferrin receptors made in insect cells do not form intermolecular disulfide bonds, but are recognized by the anti-transferrin receptor antibody, B3/25, and bind specifically to a human transferrin-Sepharose column. Binding studies using 125I-labeled human transferrin showed that insect cells infected with the recombinant virus expressed an average of 5.8 +/- 0.9 X 10(5) transferrin receptors (Kd = 63 +/- 9 nM) on their cell surface. Thus, the human transferrin receptor produced in insect cells is biologically active and appears suitable for structural and functional studies.

Effect of an anti-murine transferrin receptor-ricin A conjugate on bone marrow stem and progenitor cells treated in vitro.

A monoclonal antibody with specificity for murine transferrin receptor was conjugated with the toxic A subunit of ricin. The dose range, specificity, and kinetics of inhibition of protein synthesis of the conjugate were determined on the murine T-lymphoma cell line, BW5147. When toxin was present throughout the period of culture, in vitro myeloid (CFUc) and erythroid (CFUe and BFUe) bone marrow colonies were inhibited by doses of conjugate comparable to those that inhibit protein synthesis in murine cell lines (IC50 of 5 X 10(-11)M). Bone marrow exposed briefly (30 min to 6 h) to anti-transferrin receptor antibody-ricin A conjugate was assayed for myeloid (CFUc) and erythroid (CFUe and BFUe) progenitors in vitro and for in vivo spleen colony formation (CFUs). Only CFUe were depleted by this pulse exposure, consistent with the higher frequency of proliferating cells and transferrin receptor expression in the CFUe population relative to other progenitors.