Albers-Schönberg disease, or autosomal dominant osteopetrosis, type II (ADO II), is the most common form of osteopetrosis, a group of conditions characterized by an increased skeletal mass due to impaired bone and cartilage resorption. Following the assignment of the gene causing ADO II to chromosome 16p13.3, we now report seven different mutations in the gene encoding the ClCN7 chloride channel in all 12 ADO II families analysed. Additionally, a patient with the severe, autosomal recessive, infantile form of osteopetrosis (ARO) was identified as being homozygous for a ClCN7 mutation. From genotype-phenotype correlations, it seems that ADO II reflects a dominant negative effect, whereas loss-of-function mutations in ClCN7 do not cause abnormalities in heterozygous individuals. Because some ARO patients have mutations in both copies of the ClCN7 gene, ADO II is allelic with a subset of ARO cases.

No abstract

A markedly elevated BB isoenzyme fraction of serum creatine kinase was noted in four male siblings and correlated with typical radiographic findings of autosomal dominant osteopetrosis Type II (ADO Type II). Patients with other sclerosing bone diseases had no elevation of CK‐BB. The precision of the electrophoretic mobility patterns and correlation by I‐125 tagged radioimmunoassay method confirms that this is CK‐BB. We postulate that the dysfunctional and/or immature osteoclasts in ADO are more dependent on CK‐BB than on the usual tricarboxylic acid cycle for the production of energy. The correlation of marked elevation of serum CK‐BB with radiographic evidence of ADO Type II may prove to be of value as a biologic marker in the early diagnosis of the illness and lead to better understanding of the metabolism of bone.

Only three previous reports on the ultrastructural appearance of tibial adamantinoma have been found among some 120 cases of this tumor reported in the literature. The tumor in our case is less differentiated than the cases previously reported. We believe it is of epithelial character and the possibilities of its histogenesis have been narrowed down to either mesothelial, synovial or squamous origins among the many theories proposed. Ameloblastic origin, however, cannot be ruled out.

A patient with necrotizing sialometaplasia of the hard palate was treated with wide resection on a biopsy diagnosis of carcinoma. The literature on this recently identified entity is reviewed and the characteristic clinical features, histopathology and ultrastructure are summarized. To the best of our knowledge, no ultrastructural study concerning this entity has been previously reported. Unless recognized early, an extensive resection might be done needlessly.