Michael J. Aldred

SHH mutation is associated with solitary median maxillary central incisor: A study of 13 patients and review of the literature†

Solitary median maxillary central incisor (SMMCI) or single central incisor is a rare dental anomaly. It has been reported in holoprosencephaly (HPE) cases with severe facial anomalies or as a microform in autosomal dominant HPE (ADHPE). In our review of the literature, we note that SMMCI may also occur as an isolated finding or in association with other systemic abnormalities. These anomalies include short stature, pituitary insufficiency, microcephaly, choanal atresia, midnasal stenosis, and congenital nasal pyriform aperture stenosis. SMMCI can also be a feature of recognized syndromes or associations or a finding in patients with specific chromosomal abnormalities. We performed a molecular study on a cohort of 13 SMMCI patients who did not have HPE. We studied two genes, Sonic Hedgehog (SHH) and SIX3, in which mutations have been reported in patients showing SMMCI as part of the HPE spectrum. A new missense mutation in SHH (I111F), segregating in one SMMCI family, was identified. Our results suggest that this mutation may be specific for the SMMCI phenotype since it has not been found in the HPE population or in normal controls. Published 2001 Wiley-Liss, Inc.

DLX3 mutation associated with autosomal dominant amelogenesis imperfecta with taurodontism

Amelogenesis imperfecta hypoplastic‐hypomaturation with taurodontism (AIHHT) is an autosomal dominant (AD) trait associated with enamel defects and enlarged pulp chambers. In this study, we mapped an AIHHT family to human chromosome 17 q21‐q22 (lod score 3.3) and identify a two basepair deletion (CT) at nucleotide 560 in DLX3 associated with the disease. This mutation causes a frameshift altering the last two amino acids of the DNA‐binding homeodomain introducing a premature stop codon truncating the protein by 88 amino acids. This is the first report of a mutation within the homeodomain of DLX3. Previous studies have shown a DLX3 mutation outside the homeodomain associated with tricho‐dento‐osseous syndrome (TDO) suggesting TDO and some forms of AIHHT are allelic. copy; 2005 Wiley‐Liss, Inc.

Solitary median maxillary central incisor, short stature, choanal atresia/midnasal stenosis (SMMCI) syndrome

This article describes a series of 21 consecutive cases, each involving a solitary median maxillary central incisor; the patients were seen in the Department of Dentistry or the Victorian Clinical Genetics Unit, Murdoch Institute, at the Royal Childrens Hospital, Melbourne, from 1966 to 1997. The spectrum of anomalies and associated features present in these cases--solitary median maxillary central incisor, choanal atresia, and holoprosencephaly--is described, and the literature related to the features, including genetic studies in these conditions, is reviewed. We relate our findings in these cases to current knowledge of developmental embryology. It is hoped that the findings, together with our interpretation of them, will help to clarify understanding of solitary median maxillary central incisor syndrome. This syndrome was previously considered a simple midline defect of the dental lamina, but it is now recognized as a possible predictor of holoprosencephalies of varying degrees in the proband, in members of the probands family, and in the familys descendants.

Oral focal mucinosis: report of 15 cases and review of the literature

Aims: To describe 15 cases of oral focal mucinosis (OFM) and compare these to previously reported cases. Methods: Cases diagnosed as OFM in the period 1981‐2003‐were reviewed. Clinical information provided at the time of submission of each specimen was retrieved and supplemented by additional clinical details provided by the respective clinician at the time of compilation of this paper. The literature was reviewed. Results: OFM presented as an innocuous soft tissue swelling that may be either pedunculated or sessile. The gingiva was confirmed as the most common site for OFM, with a predominance of females affected. Microscopically, OFM is characterised by an area of myxoid tissue which is usually well‐defined. The lesion is periodic acid‐Schiff (PAS)‐negative and alcian blue‐positive, with pre‐digestion with hyaluronidase preventing the alcian blue staining. As the differential diagnosis includes myxoid neural lesions, S100 staining is important in establishing the diagnosis, with cases of OFM being negative. Conclusions: The cause of OFM remains unknown. The cases presented in this paper bring OFM to the attention of anatomical pathologists when considering the differential diagnosis of myxoid lesions of the oral cavity.

Calcium oxalate crystals in a nasolabial cyst

To our knowledge, this is the first report of calcium oxalate crystals in a cyst of the oral cavity. No underlying systemic disorder could be identified. It is proposed that this represents a dystrophic process, possibly related to inflammation, although the mechanism of the crystal formation is uncertain.