The Louis-Bar syndrome or Ataxia-Teleangiectasia (AT) is one of the rare inherited disease states in man associated with raised frequencies of chromosome aberrations in cell cultures. It is proved that not all the patients display these peculiar rearrangements; however, as a general rule, most of them show an increased frequency of chromatidic and chromosome-type aberrations, dicentric formation by end-to-end fusions, normal rate of sister chromatidic exchange, clones of cytogenetically abnormal cells, most often involving the chromosome 14. Skin fibroblasts of affected individuals show a higher proportion of chromosome breakage than lymphocytes. Increased rates of chromosome changes are probably present also in some phenotypically normal family members when compared to normal controls. In the present study cytogenetic investigations have been carried out on peripheral blood cultured lymphocytes in 9 AT patients and in 11 family members. In 8 patients the frequency of aberrations ranged between 8% and 17% and included increased rates of chromatidic and chromosome type aberrations, dicentrics, and the presence, in 7 cases, of a large acrocentric marker chromosome resulting from translocation t (14;14)(q12;q32). The rates of chromosome damage consistently increased in the 6 patients' parents (obligate heterozygotes for the AT gene), in which the percentage of abnormalities was 6.48%. Although not all the AT patients show elevated chromosome breakage rates and their lymphocytes reveal significantly less damage than individuals affected with other 'spontaneous breakage syndromes' (like Bloom's and Fanconi's), the data of the present investigation confirm the presence of specific chromosome aberrations in the Louis-Bar syndrome. In fact, the dicentric formation and the clones consistently involving the long arm of chromosome 14 seem to be representative of this disease, as the quadriradials observed in Bloom syndrome. The specificity of the involvement of chromosome 14 is of particular interest, because of the observation of a similar abnormality under some preneoplastic and neoplastic conditions. However, the etiological relationship between the presence of the marker chromosome or the formation of pseudodiploid clones and the development of malignant diseases in the patients needs to be supported by additional data.
|Translated title of the contribution||Common chromosome aberrations in patients with Louis Bar syndrome (ataxia teleangiectasia)|
|Number of pages||10|
|Journal||Rivista Italiana di Pediatria|
|Publication status||Published - 1977|
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health