Heat shock protein 27 (HSP27) is one of a number of actin-binding proteins that regulate actin polymerization. Three related HSP27 sequences had previously been mapped to chromosomes 3, 9, and X. We have used fluorescent in-situ hybridization (FISH) to correct and refine the map position of the transcribed HSP27 gene (locus HSPB1) to chromosome 7q11.23. This band also contains the site of the deletion associated with Williams syndrome (WS). To define the relationship between HSP27 and the WS deletion, we used two-color FISH on previously G-banded and photographed metaphase chromosomes from WS cell-lines and peripheral blood. Six WS patients with longer deletions that extend telomeric to the classical WS deletion region were analyzed for deletion length using HSP27, cosmids generated from P193O22 (cos11) and B350L10 (cos64 and 82), B350L10, B161A02, and B363M4. The BAC 363M4 was selected from the Washington University database and contains HSP27. Our results indicated that HSP27 was deleted in three patients and that HSP27 is telomeric to cos11, cos64, cos82, and B350L10. B363M4 was demonstrated to overlap the telomeric end of B161A02 and HSP27 may be contained partially within the telomeric end of B161A02. The possible role of HSP27 in the cognitive features of WS is discussed.

IER3 ( formerly IEX-1) encodes a 27-kDa glycoprotein that regulates death receptor-induced apoptosis, interacts with NF-KB pathways, and increases expression rapidly in response to cellular stresses such as irradiation. Animal models, gene expression microarray experiments, and functional studies in cell lines have suggested a potential role for IER3 in oncogenesis, but, to date, no abnormalities of IER3 at the DNA level have been reported in patients with neoplasia. Here, we describe breakpoint cloning of a t(6;9)(p21;q34) translocation from a patient with a myelodysplastic syndrome (MDS), facilitated by conversion technology and array-based comparative genomic hybridization, which revealed a rearrangement translocating the IER3 coding region away from critical flanking/regulatory elements and to a transcript-poor chromosomal region, markedly decreasing expression. Using splitsignal and locus-specific fluorescence in situ hybridization (FISH) probes, we analyzed 204 patients with diverse hematological malignancies accompanied by clonal chromosome 6p21 abnormalities, and found 8 additional patients with MDS with IER3 rearrangements (translocations or amplification). Although FISH studies on 157 additional samples from patients with MDS and a normal-karyotype were unrevealing, and sequencing the IER3 coding and proximal promoter regions of 74 MDS patients disclosed no point mutations, reverse transcription-PCR results suggested that dysregulated expression of IER3 is common in MDS (61% >4-fold increase or decrease in expression with decreased expression primarily in early MDS and increased expression primarily in later MDS progressing toward leukemia), consistent with findings in previous microarray experiments. These data support involvement of IER3 in the pathobiology of MDS.

We describe an infant with trisomy of (5)(p10p13.1) resulting from a de novo marker chromosome. The marker's origin was identified by chromosome microdissection and reverse in situ hybridization. The clinical findings are compared to those of other partial and complete 5p duplications. This case further defines the critical region of 5p trisomy syndrome to proximal 5p.

Cytogenetic analysis was performed on short-term cultures of primary tumor samples from seven patients with posterior uveal melanoma. Informative data were obtained from four patients, all of whom had a near-diploid chromosomal number and clonal chromosomal alterations. Analysis of one patient's tumor revealed monosomy 3 as the only cytogenetically distinguishable aberration. Trisomies of chromosome 8 and i(8)(q10) were detected in two other patients in combination with monosomy of chromosome 3. The fourth patient's karyotype displayed two different translocations. One translocation, der(6)t(6;8)(q12;q13.1), resulted in the over-representation of 8q13.1-->qter and a partial monosomy of 6q12-->qter; the other translocation, der(9)t(6;9)(p12;p23), produced a partial trisomy of 6p12-->pter and a partial monosomy of 9p23-->pter. These results support the view that the recurring pattern of chromosomal rearrangements in ocular melanoma is unique from that associated with cutaneous malignant melanoma. Furthermore, these results help confirm that chromosomes 3, 6, and 8 are nonrandomly altered in ocular melanoma.

Background: Sirenia (manatees, dugongs and Stellar's sea cow) have no evolutionary relationship with other marine mammals, despite similarities in adaptations and body shape. Recent phylogenomic results place Sirenia in Afrotheria and with elephants and rock hyraxes in Paenungulata. Sirenia and Hyracoidea are the two afrotherian orders as yet unstudied by comparative molecular cytogenetics. Here we report on the chromosome painting of the Florida manatee.