International collaborative study on ghost cell odontogenic tumours: calcifying cystic odontogenic tumour, dentinogenic ghost cell tumour and ghost cell odontogenic carcinoma.

BACKGROUND: Calcifying odontogenic cyst was described first by Gorlin et al. in 1962; since then several hundreds of cases had been reported. In 1981, Praetorius et al. proposed a widely used classification. Afterwards, several authors proposed different classifications and discussed its neoplastic potential. The 2005 WHO Classification of Odontogenic Tumours re-named this entity as calcifying cystic odontogenic tumour (CCOT) and defined the clinico-pathological features of the ghost cell odontogenic tumours, the CCOT, the dentinogenic ghost cell tumour (DGCT) and the ghost cell odontogenic carcinoma (GCOC). METHODS: The aim of this paper was to review the clinical-pathological features of 122 CCOT, DGCT and GCOC cases retrieved from the files of the oral pathology laboratories from 14 institutions in Mexico, South Africa, Denmark, the USA, Brazil, Guatemala and Peru. It attempts to clarify and to group the clinico-pathological features of the analysed cases and to propose an objective, comprehensive and useful classification under the 2005 WHO classification guidelines. RESULTS: CCOT cases were divided into four sub-types: (i) simple cystic; (ii) odontoma associated; (iii) ameloblastomatous proliferating; and (iv) CCOT associated with benign odontogenic tumours other than odontomas. DGCT was separated into a central aggressive DGCT and a peripheral non-aggressive counterpart. For GCOC, three variants were identified. The first reported cases of a recurrent peripheral CCOT and a multiple synchronous, CCOT are included. CONCLUSIONS: Our results suggest that ghost cell odontogenic tumours comprise a heterogeneous group of neoplasms which need further studies to define more precisely their biological behaviour.

Expanding the phenotype of SPONASTRIME dysplasia to include short dental roots, hypogammaglobulinemia, and cataracts.

SPONASTRIME dysplasia (SD) is an autosomal recessive skeletal dysplasia of the spondyloepimetaphyseal dysplasia (SEMD) type. The name was derived from "spondylar and nasal alterations with striated metaphyses" [Fanconi et al. 1983; Helv Paediat Acta 38: 267-280]. We follow two previously reported patients with SD [Patients 3, 4 in Langer et al. 1996; Am J Med Genet 63: 20-27]. Since the original publication, additional findings were identified in these patients.

Oculofaciocardiodental and Lenz microphthalmia syndromes result from distinct classes of mutations in BCOR.

Lenz microphthalmia is inherited in an X-linked recessive pattern and comprises microphthalmia, mental retardation, and skeletal and other anomalies. Two loci associated with this syndrome, MAA (microphthalmia with associated anomalies) and MAA2, are situated respectively at Xq27-q28 (refs. 1,2) and Xp11.4-p21.2 (ref. 3). We identified a substitution, nt 254C-->T; P85L, in BCOR (encoding BCL-6-interacting corepressor, BCOR) in affected males from the family with Lenz syndrome previously used to identify the MAA2 locus. Oculofaciocardiodental syndrome (OFCD; OMIM 300166) is inherited in an X-linked dominant pattern with presumed male lethality and comprises microphthalmia, congenital cataracts, radiculomegaly, and cardiac and digital abnormalities. Given their phenotypic overlap, we proposed that OFCD and MAA2-associated Lenz microphthalmia were allelic, and we found different frameshift, deletion and nonsense mutations in BCOR in seven families affected with OFCD. Like wild-type BCOR, BCOR P85L and an OFCD-mutant form of BCOR can interact with BCL-6 and efficiently repress transcription. This indicates that these syndromes are likely to result from defects in alternative functions of BCOR, such as interactions with transcriptional partners other than BCL-6. We cloned the zebrafish (Danio rerio) ortholog of BCOR and found that knock-down of this ortholog caused developmental perturbations of the eye, skeleton and central nervous system consistent with the human syndromes, confirming that BCOR is a key transcriptional regulator during early embryogenesis.

New syndrome: focal dermal hypoplasia, morning glory anomaly, and polymicrogyria.

Regional skin hypoplasia has been described in several genetic syndromes, including focal dermal hypoplasia (FDH), microphthalmia with linear skin defects (MLS), oculocerebrocutaneous syndrome (OCCS), and terminal osseous dysplasia and pigmentary defects (TODP). All but OCCS have been reported to follow an X-linked inheritance pattern. We describe a 14-year-old girl with clinical features overlapping with these disorders. She had mild mental retardation, macrocephaly, microphthalmia, right-sided morning glory optic disc anomaly, palmar and lip pits, and polysyndactyly. A swirling pattern of skin hypopigmentation, papular hypopigmented and herniated skin lesions reminiscent of FDH most prominent over her face, head, hands, and feet was evident. Brain magnetic resonance imaging (MRI) showed polymicrogyria (most severely in the perisylvian and mesial frontal regions), enlarged left lateral ventricle, partial agenesis of the corpus callosum, and optic nerve tumor on the right. Dermatopathologic examination of the skin lesions was consistent with basaloid follicular hamartomas. The skin and digit anomalies observed overlap with FDH, but polymicrogyria, basaloid follicular hamartomas, optic nerve tumor, and morning glory anomaly have not previously been described in FDH. Skin defects in MLS are linear and the eyes typically have sclerocornea. Polymicrogyria has been described in OCCS, but not in any of the other three syndromes. The limb anomalies in TODP are reductions rather than polysyndactyly. Skin defects are localized to the face, and digital fibromas usually occur. While significant overlap exists between all four of the syndromes discussed, we believe that the constellation of anomalies observed in this girl most likely comprises a newly recognized syndrome.

Clinical homogeneity and genetic heterogeneity in Weill-Marchesani syndrome.

Weill-Marchesani syndrome (WMS) is a rare condition characterized by short stature, brachydactyly, joint stiffness, and characteristic eye abnormalities including microspherophakia, ectopia of lens, severe myopia, and glaucoma. Both autosomal recessive (AR) and autosomal dominant (AD) modes of inheritance have been described for WMS. A locus for AR WMS has recently been mapped to chromosome 19p13.3-p13.2 while mutation within the fibrillin-1 gene (15q21.1) was found in one AD WMS family. In order to answer the question of whether or not genetic heterogeneity could be related to a clinical heterogeneity, we reviewed 128 WMS patients from the literature (including 57 AR, 50 AD, and 21 sporadic cases), with a particular attention to clinical features. Statistical analyses using Fischer exact test were used to compare the proportions of 12 clinical parameters between AR and AD patients. There was no significant difference between both groups for myopia, glaucoma, cataract, short stature, brachydactyly, thick skin, muscular build, and mental retardation. Significant results were found for microspherophakia (94% in AR, 74% in AD, Fischer 0.007), ectopia lentis (64% in AR, 84% in AD, Fischer 0.016), joint limitations (49% in AR, 77% in AD, Fischer 0.010), and cardiac anomalies (39% in AR, 13% in AD, Fischer 0.004). Nevertheless, we failed to distinguish AR from AD inheritance in individual cases. These results support the clinical homogeneity but the genetic heterogeneity of WMS.

Multiple macrodontic multituberculism.

Ekman-Westborg and Julin [1974: Oral Surg 38:217-222], described multiple macrodontia and multituberculism affecting the teeth without other anomalies (E-WJ). We describe a Chilean case in a 12-year-old with the typical dental alterations and with histopathologic findings that include absence of predentin layer and prominent reduced enamel epithelium. E-WJ is not a syndrome and we propose "multiple macrodontic multituberculism" as a better name for this anomaly of uncertain etiology affecting only the crowns of the teeth.

Designation of the TARP syndrome and linkage to Xp11.23-q13.3 without samples from affected patients.

The Robin sequence is a well-known cause of cleft palate and can be sporadic or familial, isolated or syndromic. We present a four-generation family with a lethal disorder inherited in an X-linked recessive pattern that includes Talipes equinovarus, Atrial septal defect, Robin sequence, and Persistence of the left superior vena cava. We have designated this disorder "TARP" syndrome. All affected males die in infancy of unknown causes. An X-chromosome linkage scan was performed using 14 unaffected members of a single large family and 40 STRP markers. The gene was mapped to an 11-cM region in Xp11.23-q13.3. Markers DXS1003 and DXS8092 flank the region and three-point linkage analyses revealed a maximum LOD score of 2.75 at marker DXS1039. We have designated this locus as TARP. This locus was mapped without genotyping any affecteds and demonstrates that rare, lethal disorders can be evaluated by genetic linkage, even when no affected probands are available for study.

Mutations in the chemokine receptor gene CXCR4 are associated with WHIM syndrome, a combined immunodeficiency disease.

WHIM syndrome is an immunodeficiency disease characterized by neutropenia, hypogammaglobulinemia and extensive human papillomavirus (HPV) infection. Despite the peripheral neutropenia, bone marrow aspirates from affected individuals contain abundant mature myeloid cells, a condition termed myelokathexis. The susceptibility to HPV is disproportionate compared with other immunodeficiency conditions, suggesting that the product of the affected gene may be important in the natural control of this infection. We describe here the localization of the gene associated with WHIM syndrome to a region of roughly 12 cM on chromosome 2q21 and the identification of truncating mutations in the cytoplasmic tail domain of the gene encoding chemokine receptor 4 (CXCR4). Haplotype and mutation analyses in a pedigree transmitting myelokathexis as an apparently autosomal recessive trait support genetic heterogeneity for this aspect of the WHIM syndrome phenotype. Lymphoblastoid cell lines carrying a 19-residue truncation mutation show significantly greater calcium flux relative to control cell lines in response to the CXCR4 ligand, SDF-1, consistent with dysregulated signaling by the mutant receptor. The identification of mutations in CXCR4 in individuals with WHIM syndrome represents the first example of aberrant chemokine receptor function causing human disease and suggests that the receptor may be important in cell-mediated immunity to HPV infection.

Localized mutations in the gene encoding the cytoskeletal protein filamin A cause diverse malformations in humans.

Remodeling of the cytoskeleton is central to the modulation of cell shape and migration. Filamin A, encoded by the gene FLNA, is a widely expressed protein that regulates re-organization of the actin cytoskeleton by interacting with integrins, transmembrane receptor complexes and second messengers. We identified localized mutations in FLNA that conserve the reading frame and lead to a broad range of congenital malformations, affecting craniofacial structures, skeleton, brain, viscera and urogenital tract, in four X-linked human disorders: otopalatodigital syndrome types 1 (OPD1; OMIM 311300) and 2 (OPD2; OMIM 304120), frontometaphyseal dysplasia (FMD; OMIM 305620) and Melnick-Needles syndrome (MNS; OMIM 309350). Several mutations are recurrent, and all are clustered into four regions of the gene: the actin-binding domain and rod domain repeats 3, 10 and 14/15. Our findings contrast with previous observations that loss of function of FLNA is embryonic lethal in males but manifests in females as a localized neuronal migration disorder, called periventricular nodular heterotopia (PVNH; refs. 3-6). The patterns of mutation, X-chromosome inactivation and phenotypic manifestations in the newly described mutations indicate that they have gain-of-function effects, implicating filamin A in signaling pathways that mediate organogenesis in multiple systems during embryonic development.