1/2. Possible new variant of nijmegen breakage syndrome.We report on a child with microcephaly, small facial and body size, and immune deficiency. The phenotype is consistent with nijmegen breakage syndrome (NBS), with additional clinical manifestations and laboratory findings not reported heretofore. Most investigations, including the results of radiation-resistant dna synthesis, concurred with the diagnosis of NBS. cytogenetic analysis documented abnormalities in virtually all cells examined. Along with the high frequency of breaks and rearrangements of chromosomes 7 and 14, we found breakage and monosomies involving numerous other chromosomes. Because of some variation in the clinical presentation and some unusual cytogenetic findings, we suggest that our patient may represent a new variant of nijmegen breakage syndrome.- - - - - - - - - - ranking = 1keywords = breakage syndrome, breakage (Clic here for more details about this article) |
2/2. A variant of the nijmegen breakage syndrome with unusual cytogenetic features and intermediate cellular radiosensitivity.We report the first Italian case of nijmegen breakage syndrome (NBS). The proband is an immunodeficient, microcephalic, 11 year old boy with a "bird-like" face. He developed a T cell rich B cell lymphoma. Spontaneous chromosomal instability was detected in T and B lymphocytes and fibroblasts; chromosomes 7 and 14 were only sporadically involved in the rearrangements and no clonal abnormality was present. The patient appeared to be sensitive both to ionising radiation and to bleomycin, although his sensitivity did not reach the level of AT reference cells. After bleomycin treatment, inhibition of dna synthesis was low when compared with normal cells, but higher than observed in an AT reference strain. Moreover, cell cycle analysis, after drug exposure, showed a progressive reduction in the percentage of s phase cells, but the G1 arrest, found in normal cells, was not observed. On clinical evaluation our patient shares features with NBS subjects, but cytogenetic and cell biological data do not completely overlap with those reported in nijmegen breakage syndrome. The ethnic origin of our patient might account for these differences, as expression of different allelic forms at the NBS locus.- - - - - - - - - - ranking = 0.99291541195168keywords = breakage syndrome, breakage (Clic here for more details about this article) |