Non-disjunction of chromosome 21, alphoid DNA variation, and sociogenetic features of Down syndrome.

The analysis of non-disjunction of chromosome 21 and alphoid DNA variation by using cytogenetic and molecular cytogenetic techniques (quantitative fluorescence in situ hybridization) in 74 nuclear families was performed. The establishment of possible correlation between alphoid DNA variation, parental age, environmental effects, and non-disjunction of chromosome 21 was made. The efficiency of techniques applied was found to be 92% (68 from 74 cases).

[Clinical and biological significance of chromosome disorders in acute leukemia in children].

Chromosomal examination was made in the bone marrow and lymphocytes of the peripheral blood of 37 children with acute leukemia. Of them 25 had acute lymphoblastic leukemia (ALL), 12 had acute nonlymphoblastic leukemia (ANLL). NA karyotype was registered in 13 patients (5 with ALL, 9 with ANLL), AA karyotype in 17 children (12 with ALL, 5 with ANLL).