Diagnostic role of conventional cytogenetics and fluorescence in situ hybridization (FISH) in chronic myeloid leukemia patients.

INTRODUCTION: The limitation of cytogenetic analysis is that the Ph chromosome cannot be detected in clumped metaphase or in interphase cells. Fluorescence in situ hybridization (FISH) is a highly sensitive molecular genetic technique, which enables to detect break point cluster region--Abelson (BCR-ABL) complex and minimal residual disease in all Ph positive CML patients not only in metaphase but also in interphase cells. AIMS: To detect Ph chromosome in CML patients by the use of conventional cytogenetics and FISH. MATERIAL AND METHODS: The bone marrow samples were collected in heparinised syringe from 35 diagnosed CML patients and transported to cytogenetic laboratory for chromosomal analysis. Conventional karyotype was prepared by direct harvesting and short-term culture. The FISH analysis was carried out on interphase cells of two patients to confirm the cytogenetic diagnosis. RESULTS: Out of 35 CML patients, 17 (49.9%) were 100% Philadelphia positive, 10(28.5%) were 50-70% Ph+ mosaics and 3(9%) were 100% Ph negative. In 5 patients (14.25%) cytogenetic analysis failed to confirm the presence or absence of Ph chromosome. FISH was carried out in interphase cells from bone marrow preparations of two patients. The signals for BCR-ABL fusion gene was absent in Ph- negative CML patients. In Ph positive patients, the FISH analysis detected BCR-ABL fusion gene seen as a yellow signal on interphase cells. CONCLUSION: Conventional cytogenetics is a useful method for detection of Ph chromosome in metaphase stage of cell division. FISH can be used in interphase stage of cell division for the same purpose.

Disseminated Langerhans cell histiocytosis-an interesting case report with concise review of literature.

A 2-year-old boy presented with fever, recurrent infections and multiple skin lesions. He had anemia, eczematous skin lesions, cervical lymph node enlargement, hepatomegaly and lytic lesions on skull x-ray. The skin infiltrates were CD 68, CD 1a positive and S100 positive. He was diagnosed as disseminated langerhans cell histiocytosis. The occurrence of histiocytosis is reviewed and possible treatment is discussed.

Distribution of C282Y and H63D mutations in the HFE gene in healthy Asian Indians and patients with thalassaemia major.

BACKGROUND: Mutations in the HFE gene have been shown to be strongly associated with hereditary haemochromatosis, an autosomal recessive disease of iron overloading. The majority of patients with hereditary haemochromatosis possess a homozygous mutation C282Y that disrupts the binding of the HFE gene with beta2 microglobulin and prevents its surface expression. Another HFE mutation H63D is known to increase the relative risk of developing hereditary haemochromatosis. This disease is rare in India although secondary haemochromatosis is commonly seen among children suffering from thalassaemia major. The status of HFE mutations has not been explored among Indians, particularly in patients with thalassaemia major. It is also possible that in India clinical haemochromatosis could be masked by iron deficiency. METHODS: We examined a cohort of 59 unrelated, healthy individuals from north India, 57 from south India and 75 thalassaemia major patients from north India for HFE mutations (C282Y and H63D) in cis/trans by the polymerase chain reaction sequence-specific primer method. RESULTS: The C282Y and H63D mutations in the HFE gene were rare among Indians. Although the HFE mutations were increased among patients of thalassaemia their effect on iron burden or disease pathogenesis remains unclear. CONCLUSIONS: Hereditary haemochromatosis is rarely observed among Indians and so are the C282Y and H63D mutations in the HFE gene. Long-term follow up studies would be required to determine whether the relatively higher frequency of these mutations among patients of thalassaemia has any influence on iron accumulation.