Objective: Multiple myeloma (MM) is a clinically and genetically heterogeneous plasma cell neoplasm. The prognosis of MM patients is dependent on several factors including the patient’s age, the stage of disease and genetic alterations. This study aimed to determine the frequency of common chromosomal abnormalities and their significance in MM patients referred to a tertiary healthcare center in India. Methods: Fluorescence in situ hybridization on interphase nuclei from bone marrow cells using seven MM-specific probes for recurrent aberrations was performed in a total of 215 newly diagnosed patients. Results: Chromosomal abnormalities were detected in 161 (74.9%) MM patients in this study. The most frequent aberration was trisomy(ies) involving only gain of chromosomes in 48 (22.3%) cases. A translocation involving the IGH gene alone or accompanied by trisomy(ies) or by monosomy 13/13q deletion or by both was registered in 80 (37.2%) patients. Atypical patterns such as a deletion of the IGH variable segment (IGHv) on the derivative chromosome 14 or on the native (normal) chromosome 14, biallelic deletion of IGHv, deletion of the IGH constant segment on the rearranged chromosome14 and extra fusions were noticed in 21 (9.8%) patients with an IGH rearrangement. Monosomy 13/deletion 13q was identified singly or as part of a complex karyotype in 74 patients (34.4%). Clonal heterogeneity and additional abnormalities including TP53 deletion and monosomies of chromosomes 4, 9, 14 and 16 were recorded in 18.6% and 16.3% of patients respectively. Patients with abnormalities exhibited plasmacytosis, reduced hemoglobin value and high level of ß2-microglobulin. Conclusions: A lower median age and a low frequency of IGH translocations particularly t(11;14) and chromosome 13 abnormalities suggest ethnic diversity. Further investigations on genetic alterations including IGH deletions will contribute to improved insights into the biology of myeloma disease, risk stratification and patient management.

The most common aneuploidies observed in prenatal diagnostics in the second trimester are trisomies of the chromosomes 13, 18 or 21 and gonosomal abnormalities. Rapid detection of these aneuploidies after amniocentesis is possible by fluorescence in situ hybridization (FISH) utilizing centromeric or locus-specific probes. FISH aneuploidy screening results in uncultured amniocytes are available within 24 h or less. Operators should be aware that there are possible pitfalls in connection with the commercially available probe sets and in result interpretation in general and thus proceed with appropriate caution. Here, we explain how rapid prenatal aneuploidy screening is performed using the Food and Drug Administration (FDA-) approved Aneu Vysion kit (ABBOTT/Vysis) and a review is given of drawbacks and opportunities of the method.

BACKGROUND: The 13q deletion syndrome is a rare chromosome disorder associated with wide phenotypic spectrum, which is related to size and location of the deleted region and includes intellectual disability, growth retardation, craniofacial dysmorphisms, congenital malformations, and increased risk of retinoblastoma.
METHODS: Here, we report on a teenage boy with a mild phenotype characterized by obesity, hyperactivity, dysphagia, dysgraphia, sleep disturbance, and minor dysmorphic features (round face, bushy eyebrows, and stubby hands). Array Comparative Genomic Hybridization on blood identified a mosaic 13q14.13-13q31.1 deletion, with a mosaicism rate around 40%, which was confirmed by quantitative PCR and interphase Fluorescent In Situ Hybridization (iFISH) on both blood genomic DNA and cultured/uncultured blood lymphocytes, respectively. Conversely, karyotype analysis on blood estimated a mosaicism rate of 24% and iFISH on buccal smears revealed a borderline value of 0.4%, suggesting the absence of 13q deletion in this cell line.
CONCLUSIONS: The comparison with previous patients carrying similar deletions informed that the proband clinical presentation is the mildest reported to date, thus supporting the burden of mosaicism in modulating the phenotype also in case of large chromosomal rearrangements. Characterization of further cases by in-depth mosaicism rate in tissues with different embryonic origins might contribute in the future to a better definition of genotype-phenotype correlation, including tumor risk.

BACKGROUND: Our aim was to set the FISH combination of del(17p13), t(4;14), 1q21 gain and del(1p32), four adverse cytogenetic factors rarely evaluated together, and compare our technical thresholds with those defined in the literature.
METHODS: Two hundred thirty-three patients with MM at diagnosis were studied using FISH to target 4 unfavorable cytogenetic abnormalities: 17p13 deletion, t(4;14) translocation, 1p32 deletion and 1q21 gain. Technical thresholds were determined for each probe using isolated CD138-expressing PC from patients without MM.
RESULTS: The FISH analysis identified abnormalities in 79.0% of patients. Del(17p13) was detected in 15.0% of cases, t(4;14) in 11.5%, 1q21 gain in 37.8% and del(1p32) in 8.7%. Adding 1p32/1q21 FISH probes has enabled us to identify adverse cytogenetic profiles in 39.0% of patients without del(17p13) or t(4;14). Clonal heterogeneity was observed in 51.1% of patients as well as an increase in the number of adverse abnormalities when related clones were greater than or equal to 2 (85.1% against 45.6%).
CONCLUSIONS: FISH allowed detecting accumulation of adverse abnormalities and clonal heterogeneity in MM with a combination of 4 probes. The impacts of these two parameters need to be evaluated, and could be included in future cytogenetic classifications.

Patients with chronic lymphocytic leukemia (CLL) with 13q deletion as the sole cytogenetic abnormality usually have a favorable outcome, but the frequency of the 13q14 deletion and its impact on the outcome of other B-cell chronic lymphoproliferative disorders (BCLPDs) remain unclear. To further characterize this aberration, we investigated the prognostic significance of 13q deletion in 541 patients with BCLPDs. We performed fluorescence in situ hybridization (FISH) studies with 13q locus-specific LSI-D13S25 and LSI-RB1 probes. 52.1% of the patients with CLL harbored 13q deletion, which was significantly higher than that of other BCLPDs (p < 0.001). The size of 13q deletion was heterogeneous in both CLL and other BCLPDs. However, the distribution of cases with different deletion sizes showed no significant difference between the two groups. Whereas 13q deletion was a favorable prognostic factor in CLL, a large deletion of 13q was associated with poor prognosis in terms of time to first therapy (p = 0.020), progression-free survival (p = 0.05) and overall survival (p = 0.002) in BCLPD cases other than CLL. In conclusion, the deletion of 13q varied in size both in CLL and in other BCLPDs and adversely influenced the prognosis of patients with other BCLPDs.

Multiple myeloma is a heterogeneous disease. Its chromosomal abnormalities have been extensively studied with a view to accurate prognostication and personalized therapy. Here, we describe the techniques commonly employed for elucidating chromosomal aberrations, prognostic impact of recurrent chromosomal abnormalities, and recently updated risk stratification systems.

OBJECTIVE: We present a prenatal diagnosis and molecular cytogenetic characterization of low-level true mosaicism for trisomy 21 using uncultured amniocytes.
METHODS: A 35-year-old woman presented with a borderline-positive result of noninvasive prenatal testing for trisomy 21. She underwent amniocentesis at 18 weeks of gestation, which revealed a karyotype of 47,XY,+21(5)/46,XY(53). Repeat amniocentesis at 22 weeks of gestation revealed a karyotype of 47,XY,+21(6)/46,XY(26). Array comparative genomic hybridization (aCGH) analysis on uncultured amniocytes revealed mosaic levels of 10% to 15% for trisomy 21. Interphase fluorescence in situ hybridization (FISH) analysis on uncultured amniocytes revealed a mosaic level of 21.7% (28/129 cells) for trisomy 21. Following genetic counseling and detailed ultrasound examination, the parents decided to continue the pregnancy. The pregnancy was carried to term, and a normal 3664-g male baby was delivered. The cord blood lymphocytes had a karyotype of 47,XY,+21(2)/46,XY(38). Postnatal interphase FISH analysis of urine detected no trisomy 21 in all 39/39 urinary cells. The neonate was phenotypically normal at age 7 months.
CONCLUSIONS: Low-level true mosaicism for trisomy 21 can be associated with a favorable fetal outcome. aCGH and interphase FISH analyses on uncultured amniocytes are useful for rapid confirmation of low-level true mosaicism for trisomy 21 at repeated amniocentesis.

OBJECTIVE: This study aims to present molecular cytogenetic characterization of Pallister-Killian syndrome (PKS).
METHODS: A 37-year-old woman underwent amniocentesis at 18 weeks of gestation. Amniocentesis revealed a karyotype of 47,XY,+i(12)(p10)[6]/48,XY,+i(12)(p10)×2[1]/46,XY[6]. Repeated amniocentesis was performed at 20 weeks of gestation. Array comparative genomic hybridization (aCGH) was performed using uncultured amniocytes, cord blood, and skin. Quantitative fluorescent polymerase chain reaction (QF-PCR) was performed using uncultured amniocytes and parental bloods. Interphase fluorescence in situ hybridization (FISH) analysis was performed using uncultured amniocytes and cultured stimulated cord blood lymphocytes. Conventional cytogenetic analysis was performed using cultured cells from amniotic fluid, skin, placenta, umbilical cord, and cord blood.
RESULTS: Repeated amniocentesis revealed a mosaic tetrasomy 12p level of 25% (10/40), cultured cord blood lymphocytes had no mosaicism, cultured skin fibroblasts had a mosaic tetrasomy 12p level of 52.5% (21/40), umbilical cord fibroblasts had a mosaic tetrasomy 12p level of 72.5% (29/40), and the placental cells had a mosaic tetrasomy 12p level of 2.5% (1/40) on conventional cytogenetics. An aCGH analysis revealed that the increases in gene dosage in 12p for uncultured amniocytes, skin, and cord blood were the log2 ratios of 0.9, 0.7, and 0.7, respectively. Interphase FISH on uncultured amniocytes revealed a mosaic level of 73.1% (49/67) (tetrasomy 12p: 33; hexasomy 12p: 16). Interphase FISH analysis of stimulated cultured cord blood lymphocytes revealed a mosaic level of 58.3% (60/103) (tetrasomy 12p: 51; hexasomy 12p: 9).
CONCLUSIONS: In the diagnosis of PKS by conventional culture cytogenetics, cord blood samplings and placental samplings are prone to a negative result when compared with amniocentesis. Whenever cord blood sampling is applied for prenatal diagnosis of PKS, aCGH on uncultured cord blood or interphase FISH on cultured cord blood can be used for the diagnosis, in addition to conventional cytogenetics.

UNASSIGNED: Maternal serum screening-positive patient had prenatal diagnosis with amniotic fluid, which showed inconsistent results between interphase fluorescence in situ hybridization (three signals of 21q22.13-21q22.2) and G-banding analysis (46,XY). Further analyses proved that the fetus had extremely complex rearrangements of chromosome 21, including the interstitial duplication of Down syndrome critical region.

In Asia, the incidence of chronic lymphocytic leukaemia (CLL) is lower than in Western countries. Only a few studies of CLL have been conducted in Korea, and no long-term clinical outcome data are available. We assessed the frequency of common chromosomal aberrations in Korean CLL patients using interphase fluorescence in situ hybridization (FISH) and investigated their relationship to clinical outcomes. Between 2000 and 2011, conventional cytogenetic studies were performed in 58 patients, and FISH results were available in 48 patients. We used six DNA probes for the detection of del(13q14), trisomy 12, del(11q22), del(17p13), IGH rearrangement and del(6q23). Chromosomal aberrations were identified in 15 of 58 patients (26%) with conventional cytogenetic studies and in 25 of 48 patients (52%) with interphase FISH, including six patients with complex karyotypes. In contrast with the results of Western studies, trisomy 12 was the most common aberration, followed by IGH rearrangement, del(13q14), del(11q22) and del(17p13). Deletion of 6q23 was not observed, and isolated del(13q14) was less frequent than in Western studies. Compared with the other types of chromosomal aberrations, patients with del(11q22) and del(17p13) were more likely to be Rai stage 3-4 and Binet stage C, resulting in poor responses to chemotherapy and worse outcomes. In contrast, patient with trisomy 12 and isolated del(13q14) showed better responses and superior survival outcomes. The incidence of CLL is lower in Korea than in Western countries, and the frequency of chromosomal aberrations differs, perhaps reflecting differences in the pathogenic mechanism between ethnicities. Large prospective studies are needed to further assess the prognostic value of these results in Korean CLL patients.