Hierarchical Bayes model for random haplotype and family effects in the transmission of fragile-X

A model for the transmission of the CGG repeat sequence associated with the fragile-X dynamic mutation in the FMR1 gene is developed. The model incorporates both haplotype and family effects on the expansion rate of the sequence. The resulting random effects model is fitted to new data, using computer-intensive Markov chain Monte Carlo methods. The results demonstrate both the FRAXAC1-DXS458 haplotype and family effects on the transmission of CGG repeats from mother to offspring.

Rearrangements in the second intron of the RARA gene are present in a large majority of patients with acute promyelocytic leukemia and are used as molecular marker for retinoic acid-induced leukemic cell differentiation

Chromosome 17 breakpoints in translocation t(15;17), a hallmark for acute promyelocytic leukemia (APL), have been shown to disrupt the retinoic acid receptor-alpha (RARA) gene. In this study, DNA probes around the second exon of the RARA gene showed rearrangements not previously detected. Analysis of 25 Chinese APL cases showed that RARA gene rearrangements were present in 23 cases (92%). The breakpoints were mapped unequivocally in 22 cases within the second intron of the gene. Therefore, the RARA gene rearrangement provides us with a specific marker of the disease. Simultaneous molecular and cytologic studies showed that the RARA gene rearrangements persisted during the first 2 to 3 weeks of all-trans retinoic acid (ATRA) therapy when differentiated granulocytes predominated in bone marrow, while these rearrangements disappeared after achieving complete remission. These data indicate that ATRA induces differentiation of APL cells.

Basal cell carcinoma syndrome: report of 10 cases

Ten cases of basal cell carcinoma syndrome are presented. The jaw cysts were proved histopathologically to be odontogenic keratocysts. The multiple naevoid lesions on the skin were identified as basal cell carcinoma in two cases. Skeletal anomalies and intracranial calcification were present in all cases. A positive family history with others affected by the syndrome was traced in two cases.

Diagnostic value of computed tomography in parotid tumours

In 18 cases of parotid tumours, CT demonstrated their primary site, extent and invasion of surrounding tissue precisely. It was valuable in the majority of cases in differentiating benign from malignant tumours and could distinguish accurately intrinsic from extrinsic. CT sialography was superior in equivocal cases when it made the tumour easier to identify and the diagnosis more accurate.