P. Nagesh Rao

THE HUMAN NACP/ALPHA-SYNUCLEIN GENE - CHROMOSOME ASSIGNMENT TO 4Q21.3-Q22 AND TAQI RFLP ANALYSIS

NACP is a presynaptic protein that was originally identified as the precursor of NAC (non-A{beta} component of Alzheimer disease amyloid). It has a strong homology with groups of proteins called synuclein and PNP-14 that are brain-specific. The exact function of NACP remains unclear. Individuals with early-onset Alzheimer disease (AD) were found to have a mutation in the APP gene that encodes the precursor of amyloid {beta}-protein (A{beta}). To evaluate the potential presence of mutation or polymorphism in NACP, information on its chromosome localization and RFLP will be essential. In the present study the chromosome localization of the NACP gene was determined using PCR and Southern blotting analyses of somatic cell hybrids and in situ chromosome hybridization. Further, a two-allele RFLP was identified by screening genomic DNA from unrelated Caucasian individuals by using Southern blot analysis. 9 refs., 1 fig.

Identification of Sperm and Non-Sperm Male Cells in Cervicovaginal Smears Using Fluorescence In Situ Hybridization: Applications in Alleged Sexual Assault Cases

The identification of spermatozoa or constituents of seminal fluid is critical in the evaluation of alleged sexual assault victims. However, failure to identify sperm and/or elevated levels of acid phosphatase can occur for a variety of reasons. Molecular techniques, such as molecular cytogenetic analysis offers new approaches to improve on the identification of male cells in alleged sexual assault cases. Fluorescence in situ hybridization (FISH) with a Y chromosome specific DNA probe was applied to archival cervicovaginal smears from 41 alleged sexual assault cases to identify Y-bearing (male) cells. FISH identified Y-bearing sperm and non-sperm cells in 78% of the cases previously confirmed to have sperm. FISH also identified Y-bearing non-sperm male cells in 39% of the cases in which cytology did not detect spermatozoa; in one of these instances, it also detected sperm. Cervicovaginal acid phosphatase levels, determined at the time of the cervicovaginal smears, were also compared with the presence or absence of Y-positive cells. Application of this technique can detect non-spermatozoic male cells in routine cervicovaginal smears of sexual assault victims.

Molecular cytogenetic analysis of a duplication Xp in a male: further delineation of a possible sex influencing region on the X chromosome

We describe a male infant with severe mental retardation and autism with a duplication of the short arm of the X chromosome. Chromosome painting confirmed the origin of this X duplication. Molecular cytogenetic analysis with fluorescence in situ hybridization (FISH) identified one copy of the zinc finger protein on the X chromosome (ZFX) and two copies of the steroid sulfatase gene (STS), further delineating the breakpoints. Based on cytogenetic and molecular comparisons of cases from the literature of sex-reversal in dup(X),Y patients and our patient, we suggest that a possible secondary sexinfluencing gene involved in the regulation of sex determination or testis morphogenesis is present at the distal Xp21.1 to p21.2 region.

The human cornea has a high incidence of acquired chromosome abnormalities

Abstract Structurally and functionally, the human cornea is a highly specialized tissue. The corneal stromal collagen matrix is uniquely transparent and yet maintains a mechanically tough and chemically impermeable barrier between the eye and environment. We report for the first time that stromal keratocytes of the human cornea show cytogenetic abnormalities with a frequency that is unprecedented among normal tissues. The abnormalities are acquired, clonal and nonclonal, primarily aneuploid in nature, and present in normal as well as diseased corneas.

Identification of BCR-ABL Fusion on Chromosome 9 by Fluorescence In Situ Hybridization in Two Chronic Myeloid Leukemia Cases

We present two cases with hidden Philadelphia translocations that resulted from an insertion and a complex translocation. These cases were unusual in having the BCR/ABL fusion localized to chromosome 9q34. A review of cases with these uncommon presentations of BCR/ABL and prognostic presentation is presented.

Monosomy X as a recurring sole cytogenetic abnormality associated with myelodysplastic diseases

Solitary loss of the X chromosome is associated with Turner syndrome and not hematological disorders. We describe five patients with non-constitutional loss of the X chromosome as the sole cytogenetic abnormality in their bone marrow. Three of the five patients had myelodysplastic syndrome (MDS), one case had AML M-6 with evidence suggestive of an evolving MDS, and the last patient had a dysplastic marrow. A review of the literature identified sporadic reports of an association of monosomy X and several hematologic disorders, as well as a few solid tumors. In this series of patients, monosomy X as a sole non-constitutional cytogenetic abnormality in bone marrow is associated with myelodysplastic diseases. In addition, fluorescence in situ hybridization analysis with an X centromere probe indicated that monosomy X was present in erythroid precursors, myeloblasts, promyelocytes, myelocytes, metamyelocytes, granulocytes, and monocytes, while mature lymphocytes presented with two copies of the X chromosome. The molecular cytogenetic evidence supports the diagnosis of a myelodysplastic disorder in these cases and documents the potential role of FISH in hematological disease.

Study of clonality in myelodysplastic syndromes: Detection of trisomy 8 in bone marrow cell smears by fluorescence in situ hybridization

The lineage involvement in myelodysplastic syndromes (MDS) is still unclear. To determine the clonality and the evolution of the disorder, a retrospective study on bone marrow smears from seven MDS patients with trisomy 8 was performed using fluorescence in situ hybridization (FISH). We observed that the trisomy of chromosome 8 was selectively expressed in the myeloid-derived cells. No mature lymphocytes or plasma cells expressed three signals. Our studies demonstrate here the value of FISH for identifying the affected cell lineage. Furthermore, the easy quantification of the abnormal cells can help in assessing the progression of the disease.

Usefulness and limitations of serum and urine lysozyme levels in the classification of acute myeloid leukemia: an analysis of 208 cases.

The revised French-American-British (FAB) classification system for acute myeloid leukemia (AML) recommends the determination of serum lysozyme (SL) or urine lysozyme (UL) levels as an aid in distinguishing acute myeloblastic leukemia with maturation (FAB M2) from acute myelomonocytic leukemia (M4). We reviewed retrospectively 208 cases of adult leukemia in which SL and/or UL were obtained. Elevated lysozyme levels were not found in any of the M0, M3, or M7 cases, but were increased (false positive) in three (14%) M1 cases, 18 (19%) M2 cases and one (20%) M6 case. Although a UL value in excess of 3x normal was found in most cases of AML M4 and M5, only five (11%) M4 cases and three (20%) M5 cases had SL elevations of this magnitude. Lysozyme levels need to be interpreted in conjunction with other parameters for FAB classification.

Comparison of fluorescence in situ hybridization, cytogenetic analysis, and DNA index analysis to detect chromosomes 4 and 10 aneuploidy in pediatric acute lymphoblastic leukemia: a Pediatric Oncology Group study.

Purpose: Chromosome abnormalities are an important prognostic factor in childhood acute lymphoblastic leukemia (ALL). Recently, a subset of patients with hyperdiploid ALL and trisomy of chromosomes 4 and 10 has been reported to have a very favorable event-free survival. Rapid and accurate detection of these patients will allow them to be treated with highly effective and relatively nontoxic antimetubolitc therapy. Because of inherent problems associated with conventional cancer cytogenetics, we examined the efficacy of fluorescence in situ hybridization (FISH) to identify this ALL subgroup. Patients and Methods: Fifty uncultured bone marrow specimens from children with newly diagnosed ALL were examined for chromosomes 4 and 10 aneuploidy with FISH. These results were compared with routine cytogenetics and DNA Index (DI). Results: Interphase FISH cytogenetics identified the abnormal cell line(s) in all cases in which cytogenetics showed aneuploidy of chromosomes 4 and 10. In cases in which cytogenetics was not informative, FISH identified the presence of an aneuploid chromosome 4 and/or 10 cell line in concordance with the DI. Conclusions: FISH interphase cytogenetics can accurately detect chromosome 4 and 10 aneuploidy in leukemic cells. It is a rapid and clinically applicable technique that can reliably identify childhood ALL cases who have trisomy of chromosomes 4 and 10 and who have very favorable event-free survival.

Gender identification of human hair using fluorescence in situ hybridization.

Identification of the gender of hair represents relevant medicolegal evidence in criminal cases. The efficacy of Fluorescence In Situ Hybridization (FISH) using chromosome X and Y centromeric probes was tested to determine its ability to identify correctly the gender of hair. In this preliminary study, FISH correctly identified the gender of cells from hair as old as 26 days. The technique is accurate, rapid, sensitive, easily performed, and readily available. As a forensic laboratory technique, FISH shows great promise.