HMGA2 locus rearrangement in a case of acute lymphoblastic leukemia.

We report the first case of acute lymphoblastic leukemia associated with a t(9;12)(p22;q14) translocation within the HMGA2 locus. The breakpoint lies in the 5' region. Fluorescence in situ hybridization with a BAC clone covering the 5' region produced three signals versus two signals with a BAC clone covering the 3' region including intron 3 of HMGA2, which harbors most of the breakpoints described in benign mesenchymal tumors.

A 12q13 translocation involving the HMGI-C gene in richter transformation of a chronic lymphocytic leukemia.

We report a case of Richter transformation of a chronic lymphocytic leukemia with a 12q13 translocation involving the HMGI-C gene. Fluorescence in situ hybridization analysis with the use of two different cosmid pools spanning the entire HMGI-C region showed that the breakpoint on chromosome 12 was located in the HMGI-C gene, presumably within intron 3. In fact, the 3' region of HMGI-C had been translocated to a derivative chromosome 6.

A malformed girl with a de novo proximal 6q deletion.

An additional case of interstitial deletion of chromosome 6, the first with breakpoints in q12 and q14, is reported. The female infant was the malformed first child of young, healthy parents. A review of proximal 6q deletions is made.

[Severe mental retardation and slight dysmorphism in a child with a bisatellite extrachromosome: inversion duplication (15)?].

A de novo tetrasomy 15 has been reported, in a 6 years old child. The patient had severe mental retardation an minimal physical stigmata, consisting in slight skeletal and facial dismorphism. Cytogenetic analysis showed that extrachromosome, G-like long, was bisatellited and dicentric and was interpreted either as an inversion duplication 15 or as 15; G or D translocation.

t(21q21q)/r[t(21q21q)] mosaic in two unrelated patients with mild stigmata of Down's syndrome.

Two cases of t(21q21q)/r[t(21q21q)] mosaic in unrelated infants, 17 and 14 months old respectively are reported. The proportion of cells with the ring chromosome was 45% in the former, 80% in the latter. Both cases had mild manifestations of the Down's syndrome.