Enamel-renal-gingival syndrome and FAM20A mutations.

The enamel-renal syndrome of amelogenesis imperfecta (AI) and nephrocalcinosis, and the amelogenesis imperfecta-gingival fibromatosis syndrome have both been associated with mutations in FAM20A. We report on two unrelated Thai patients with three novel and one previously reported mutations in FAM20A with findings suggesting both disorders, including hypoplastic AI, gingival fibromatosis, unerupted teeth, aggressive periodontitis, and nephrocalcinosis/nephrolithiasis. Additional findings consisted of a supernumerary premolar, localized aggressive periodontitis, thin alveolar bone, vitamin D deficiency-associated hyperparathyroidism, and heterotopic calcification in other tissues, including lungs, dental pulp, gingiva, dental follicles, and periodontal tissues, and early cessation of limited menstruation. Greater promotory activity of urine on calcium oxalate crystal growth compared to controls may help to explain the pathogenesis, and suggest that FAM20A mutations can contribute to nephrocalcinosis/nephrolithiasis. Our findings expand the phenotypic spectrum of FAM20A mutations. Since both of our patients and a large number of previously reported cases had all the important features of both syndromes, including AI, renal anomalies, and gingival fibromatosis, we are convinced that these two disorders actually are the same entity. The name of enamel-renal-gingival syndrome is suggested.

Co-expression of p53 and Ki67 and lack of EBV expression in oral squamous cell carcinoma.

BACKGROUND: The objectives of the study were to determine the association between Epstein-Barr virus (EBV) and oral squamous cell carcinoma (OSCC), to compare the expression of p53 and Ki67 between normal oral mucosa, oral hyperkeratosis, oral pre-malignant dysplasia, and OSCC, and to determine the correlation between the expression of p53 and Ki67 in OSCC. METHODS: The expression of EBV mRNA was studied by in situ hybridization technique in 24 cases of OSCC, and the expression of p53 and Ki67 was investigated by immunohistochemical method in 19 cases of OSCC, 7 cases of oral pre-malignant dysplasia, 6 cases of oral hyperkeratosis, and 5 cases of normal oral epithelium. RESULTS: None of OSCC cases expressed EBV-encoded RNA (EBER) transcripts. The labeling indices (LI) of p53- and Ki67-positive cells were significantly higher in OSCC than in oral pre-malignant dysplasia, oral hyperkeratosis, and normal oral mucosa (P < 0.05). A significant correlation between the LI of p53- and Ki67-positive cells was observed in OSCC (r = 0.6; P = 0.01). CONCLUSIONS: These findings suggested that the co-expression of p53 and Ki67 may play roles in carcinogenesis of OSCC and p53 overexpression may promote cell proliferation in OSCC. Furthermore, EBV does not appear to be a risk factor for OSCC particularly in the population of northern Thailand.