Atypical XX male with the SRY gene located at the long arm of chromosome 1 and a 1qter microdeletion.

Male individuals with a 46,XX karyotype have been designated as XX males. In 80% of the cases, the presence of Yp sequences, including the male sex-determining gene, SRY, has been demonstrated by molecular and/or fluorescence in situ hybridization (FISH) analyses. In most cases, Yp sequences are located on the short arm of the X chromosome, resulting from unequal recombination between Yp and Xp during paternal meiosis.

Comparative genomic hybridisation identifies two variants of smoldering multiple myeloma.

Two variants of smoldering multiple myeloma (SMM) have been recognised: (i) an evolving type, characterised by a progressive increase in the M-protein size and short time to progression to overt multiple myeloma (MM) and (ii) a non-evolving type, with a long-lasting, stable M-protein and longer time to progression. Comparative genomic hybridisation (CGH) analyses in both subtypes of SMM (seven evolving and eight non-evolving SMM) were performed. Evolving SMM showed cytogenetic changes consistent with those found in de novo symptomatic MM (1q gains, chromosome 13 deletions) while the non-evolving variant showed no 1q gains and deletions were uncommon.

Orthotopic implantation of human hepatocellular carcinoma in mice: analysis of tumor progression and establishment of the BCLC-9 cell line.

Purpose: To allow the longitudinal investigation of molecular events associated with the progression of human hepatocellular carcinoma (HCC), we sought to develop a murine model by orthotopic implantation of tumor fragments obtained from patients diagnosed at early stage.

Experimental Design: Tumor pieces (2 x 2 mm) were implanted on the liver surface of nu/nu mice. After xenograft growing, subsequent passages were performed to achieve long-term implant viability.

High levels of chromosomal imbalances in typical and small-cell variants of T-cell prolymphocytic leukemia.

T-cell prolymphocytic leukemia (T-PLL) is a rare postthymic T-cell disorder that may show different morphologic variants and a very aggressive clinical behavior. On occasion, patients may present with an indolent clinical course and long survival. The disease is genetically characterized by the presence of complex karyotypes with recurrent alterations involving chromosomes 8, 14, and 11.

A novel mutation in the PSEN2 gene (T430M) associated with variable expression in a family with early-onset Alzheimer disease.

Background: Autosomal dominant early-onset Alzheimer disease is a heterogeneous condition that has been associated with mutations in 3 different genes: the amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2) genes. Most cases are due to mutations in the PSEN1 gene, whereas mutations in the APP and PSEN2 genes are rare.

Objective: To describe a novel mutation in the PSEN2 gene associated with early-onset autosomal dominant Alzheimer disease.

Chimeric BCR/ABL gene detected by fluorescence in situ hybridization in three new cases of Philadelphia chromosome-negative chronic myelocytic leukemia.

Three new cases are reported of cytogenetically Philadelphia-negative (Ph-) chronic myelocytic leukemia (CML), with positive BCR/ABL gene rearrangement according to a reverse transcriptase polymerase chain reaction technique. Fluorescence in situ hybridization (FISH) studies using different probes showed three different situations involving chromosomes 9 and 22 for the masked BCR/ABL fusion gene. With the use of BCR/ABL-extra signal and CEP 9 probes (Vysis, Downers Grove, IL, USA), FISH studies detected the BCR/ABL fusion gene at the end of chromosome 9 in patient 1, a BCR/ABL fusion gene on both chromosomes 22 in patient 2 (who was in an accelerated phase of CML), and a BCR/ABL fusion signal on chromosome 22 in patient 3.

Frequency of mutations in the presenilin and amyloid precursor protein genes in early-onset Alzheimer disease in Spain.

Background: The relative contribution of mutations in the presenilin (PSEN) and amyloid precursor protein genes to autosomal dominant and other early-onset Alzheimer disease (AD) cases is not well established.

Objectives: To clarify the respective contribution of the amyloid precursor protein and PSEN mutations to autosomal dominant AD and to determine its contribution to sporadic and familial nonautosomal dominant early-onset AD and familial late-onset AD in a referral-based Spanish population.

Subjects And Methods: Ninety-four patients with AD (60 with early-onset AD and 34 with late-onset AD) from 82 independent families were studied.