Pseudoxanthoma elasticum overlaps hereditary spastic paraplegia type 56.

PURPOSE: Pseudoxanthoma elasticum (PXE) is a recessive disorder involving skin, eyes and arteries, mainly caused by ABCC6 pathogenic variants. However, almost one fifth of patients remain genetically unsolved despite extensive genetic screening of ABCC6, as illustrated in a large French PXE series of 220 cases. We searched for new PXE gene(s) to solve the ABCC6-negative patients. METHODS: First, family-based exome sequencing was performed, in one ABCC6-negative PXE patient with additional neurological features, and her relatives. CYP2U1, involved in hereditary spastic paraplegia type 56 (SPG56), was selected based on this complex phenotype, and the presence of two candidate variants. Second, CYP2U1 sequencing was performed in a retrospective series of 46 additional ABCC6-negative PXE probands. Third, six additional SPG56 patients were evaluated for PXE skin and eye phenotype. Additionally, plasma pyrophosphate dosage and functional analyses were performed in some of these patients. RESULTS: 6.4% of ABCC6-negative PXE patients (n = 3) harboured biallelic pathogenic variants in CYP2U1. PXE skin lesions with histological confirmation, eye lesions including maculopathy or angioid streaks, and various neurological symptoms were present. CYP2U1 missense variants were confirmed to impair protein function. Plasma pyrophosphate levels were normal. Two SPG56 patients (33%) presented some phenotypic overlap with PXE. CONCLUSION: CYP2U1 pathogenic variants are found in unsolved PXE patients with neurological findings, including spastic paraplegia, expanding the SPG56 phenotype and highlighting its overlap with PXE. The pathophysiology of ABCC6 and CYP2U1 should be explored to explain their respective role and potential interaction in ectopic mineralization.

Dimeric Proanthocyanidins on the Stability of Dentin and Adhesive Biointerfaces.

A dentin biomodification strategy with selective proanthocyanidin (PAC)-enriched extracts reinforces dentin and dentin-resin interfaces. Enrichment of the extracts according to the degree of polymerization allows exploration of bioactive principles of PACs and structure-activity relationships. This study investigated the sustained dentin matrix biomodification and dentin-resin bioadhesion of 2 fractions consisting exclusively of B-type PAC dimers with or without a single galloyl motif (specifically, DIMERG and DIMERNG) and their precursor material, enriched grape seed extract (e-GSE; Vitis vinifera). The biomodification potential was determined by long-term evaluation of the apparent modulus of elasticity and collagen solubility (hydroxyproline release). Chemical characterization of the dentin matrix was performed by attenuated total reflectance-Fourier-transform infrared spectroscopy. The bioadhesive properties were assessed by a microtensile bond strength test at different time points, and macro-hybrid layers were produced to verify the degree of conversion of the adhesive resin. Fractions consisting of DIMERG, DIMERNG, and their precursor, e-GSE, increased the modulus of elasticity at all time points and reduced collagen degradation. Specimens treated with DIMERNG remained stable throughout 12 mo of storage, whereas a significant drop in the modulus of elasticity was observed for the DIMERG and e-GSE groups at 6 mo. The fractions and precursor did not affect the degree of resin conversion at the hybrid layer. Changes in infrared resonances corresponding to collagen cross-links in the dentin matrix occurred for all treatments. Higher bond strength was observed for dentin treated with e-GSE as compared with DIMERG and DIMERNG; all biointerfaces remained stable after 12 mo. Nongalloylated PACs mediate stable dentin biomodification, which includes protective activity against collagen degradation and reinforcement of the anchoring dentin matrix. Collectively, PACs with a higher degree of oligomerization offer a robust bioadhesion between the hydrophilic dentin matrix and the hydrophobic adhesive.

Search for ReCQL4 mutations in 39 patients genotyped for suspected Rothmund-Thomson/Baller-Gerold syndromes.

Three overlapping conditions, namely Rothmund-Thomson (RTS), Baller-Gerold (BGS) and RAPADILINO syndromes, have been attributed to RECQL4 mutations. Differential diagnoses depend on the clinical presentation, but the numbers of known genes remain low, leading to the widespread prescription of RECQL4 sequencing. The aim of our study was therefore to determine the best clinical indicators for the presence of RECQL4 mutations in a series of 39 patients referred for RECQL4 molecular analysis and belonging to the RTS (27 cases) and BGS (12 cases) spectrum. One or two deleterious RECQL4 mutations were found in 10/27 patients referred for RTS diagnosis. Clinical and molecular reevaluation led to a different diagnosis in 7/17 negative cases, including Clericuzio-type poikiloderma with neutropenia, hereditary sclerosing poikiloderma, and craniosynostosis/anal anomalies/porokeratosis. No RECQL4 mutations were found in the BGS group without poikiloderma, confirming that RECQL4 sequencing was not indicated in this phenotype. One chromosomal abnormality and one TWIST mutation was found in this cohort. This study highlights the search for differential diagnoses before the prescription of RECQL4 sequencing in this clinically heterogeneous group. The combination of clinically defined subgroups and next-generation sequencing will hopefully bring to light new molecular bases of syndromes with poikiloderma, as well as BGS without poikiloderma.

Effect of cigarette smoke on color stability and surface roughness of dental composites.

OBJECTIVE: To evaluate the color stability and surface roughness of 3 dental composites subjected to cigarette smoke and brushing. METHODS: Twenty specimens were prepared for each type of restorative material used: nanohybrid (Tetric N-Ceram); hybrid (Z250-3M ESPE) and silorane-based microhybrid (Filtek P90-3M ESPE), which were divided into 2 groups (n=10), according to the type of finishing/polishing received: Group 1 - papers with decreasing abrasive grit and Group 2 - polyester matrix (without polishing). After initial readouts of color (Easy Shade-VITA) and surface roughness (SJ-201P Mitutoyo), specimens were subjected to action of smoke from 20 cigarettes, (Marlboro Red-Philip Morris). After each cigarette, the samples were submitted to brushing in a standardised device. After this, final readouts were taken to calculate change in color (ΔE and ΔL) and roughness (ΔRa), which were statistically analysed (2-way ANOVA, Bonferroni, and Student's-t tests respectively, p<0.05). RESULTS: Tetric N-Ceram presented color change at clinically unacceptable levels (ΔE>3.3) when the polyester strip was used for finishing, a result differing (p<0.05) from those of the other composites, which presented no difference between them (p>0.05). Unpolished composites presented higher Ra values than those that were polished (p<0.05), with exception of the silorane based composite. CONCLUSION: Absence of polishing increases cigarette capacity to stain composites and surface roughness of composites, with exception of the silorane based type.

Evaluation of negative outcomes associated with medication (NOM) by pharmacists at a home assistance programme in a Brazilian teaching hospital

Background The concept of pharmaceutical care (PC) specifically refers to the pharmacist being able to identify, prevent and resolve negative outcomes associated with medication (NOM). According to the Third Consensus of Granada, these are patient health-related outcomes not consistent with pharmacotherapy objectives, and are associated with the proper or erroneous use of medicines. In this way, pharmacists might provide the pharmacist to provide the correct use of medicines to patients who are attended at home. Objective This study aimed to detect, classify and quantify NOM, according to the Third Consensus of Granada, in patients treated at home, who were assisted by the Home Assistance Programme of the University Hospital of University of Paulo, Brazil. Method A descriptive, observational and cross-sectional study was conducted. The pharmacotherapy plan was filled during the interview with the patient or caregiver. Results The study included 87 patients with a mean age of 66 years old, adults (89%), children (11%), female (58%) and retired (62%). A total of 62% patients presented NOM, with an average of 1.13 NOM per patient. The NOM included untreated health problems (20.6%), effects from unnecessary medicines (9.1%), non-quantitative ineffectiveness (34.5%), quantitative ineffectiveness (3.4%), non-quantitative safety problems (11.4%) and quantitative safety problems (3.4%). Patients with the following characteristics were more prevalent than expected in the NOM effectiveness group: those aged between 65 and 74 years (p=0.0199), those with a low education level (p=0.0266), those with increased comorbidity (p=0.0461), those using medicine for the digestive tract and (..) (AU)

Introducción Para utilizar el concepto de de Atención Farmacéutica (AF) en su más amplio significado, el farmacéutico debe haber podido identificar, prevenir y resolver los resultados negativos asociados a la medicación (RNM). Según el Tercer Consenso de Granada, estos RNM están relacionados con los resultados en la salud del paciente no adecuados al objetivo de la farmacoterapia y asociados al uso o fallo en el uso de medicamentos. Así pues, el farmacéutico puede facilitar el uso correcto de los medicamentos a los pacientes en régimen domiciliario. Objetivo El objetivo de este estudio es detectar, clasificar y cuantificar los RNM, según el Tercer Consenso de Granada, en pacientes tratados en régimen domiciliario que fueron atendidos a través del Programa de Asistencia Domiciliaria del Hospital Universitario de São Paulo en Brasil. Método Estudio descriptivo y observacional de corte transversal. La planificación del tratamiento farmacológico se completó durante la entrevista con el paciente o el cuidador. Resultados El estudio contó con 87 pacientes con una edad media de 66 años, del cual el 89% eran adultos, el 11% niños, el 58% mujeres y el 62% jubilados. El sesenta y dos por ciento de los pacientes presentó RNM, con una media de 1,13 RNM por paciente. La prevalencia de RNM fue: problemas de salud no tratados (20,62%), efecto de medicamentos innecesarios (9,1%), ineficacia no cuantitativa (34,5%), ineficacia cuantitativa (3,4%), problemas de salud no cuantitativos (11,4%) y problemas de salud cuantitativos (3,4%). La probabilidad de ocurrencia de RNM de eficacia aumentaba en pacientes con: edades de entre 65 y 74 años (p = 0,0199), nivel de educación bajo (p = 0,0266), más comorbilidades (p = 0,0461), uso de medicamentos para el (..) (AU)

Evaluation of negative outcomes associated with medication (NOM) by pharmacists at a home assistance programme in a Brazilian teaching hospital.

BACKGROUND: The concept of pharmaceutical care (PC) specifically refers to the pharmacist being able to identify, prevent and resolve negative outcomes associated with medication (NOM). According to the Third Consensus of Granada, these are patient health-related outcomes not consistent with pharmacotherapy objectives, and are associated with the proper or erroneous use of medicines. In this way, pharmacists might provide the pharmacist to provide the correct use of medicines to patients who are attended at home. OBJECTIVE: This study aimed to detect, classify and quantify NOM, according to the Third Consensus of Granada, in patients treated at home, who were assisted by the Home Assistance Programme of the University Hospital of University of Paulo, Brazil. METHOD: A descriptive, observational and cross-sectional study was conducted. The pharmacotherapy plan was filled during the interview with the patient or caregiver. RESULTS: The study included 87 patients with a mean age of 66 years old, adults (89%), children (11%), female (58%) and retired (62%). A total of 62% patients presented NOM, with an average of 1.13 NOM per patient. The NOM included untreated health problems (20.6%), effects from unnecessary medicines (9.1%), non-quantitative ineffectiveness (34.5%), quantitative ineffectiveness (3.4%), non-quantitative safety problems (11.4%) and quantitative safety problems (3.4%). Patients with the following characteristics were more prevalent than expected in the NOM effectiveness group: those aged between 65 and 74 years (p=0.0199), those with a low education level (p=0.0266), those with increased comorbidity (p=0.0461), those using medicine for the digestive tract and metabolism (p=0.0475) and those using medicine for blood and blood-forming organs (p=0.0466). For the NOM necessity group, patients with endocrine, nutritional and metabolic diseases (p=0.0587) were in greater numbers than expected; and for the NOM safety group, only patients aged over 74 years (p=0.01809) were in greater numbers. CONCLUSION: For this population, it was concluded that there were several factors related to the occurrence of NOM: age, education, number of comorbidities, use of medicines for the digestive tract and the metabolism and medicines for blood and blood-forming organs. The use of the Third Consensus of Granada classification was very important for the recognition and measurement of NOM.

Clinical and molecular characterization of Diastrophic Dysplasia in the Portuguese population.

SLC26A2-related dysplasias encompass a spectrum of diseases: from lethal achondrogenesis type 1B (ACG1B; MIM #600972) and atelosteogenesis type 2 (AO2; MIM #256050) to classical diastrophic dysplasia (cDTD; MIM #222600) and recessive multiple epiphyseal dysplasia (rMED; MIM #226900). This study aimed at characterizing clinically, radiologically and molecularly 14 patients affected by non-lethal SLC26A2-related dysplasias and at evaluating genotype-phenotype correlation. Phenotypically, eight patients were classified as cDTD, four patients as rMED and two patients had an intermediate phenotype (mild DTD - mDTD, previously 'DTD variant'). The Arg279Trp mutation was present in all patients, either in homozygosity (resulting in rMED) or in compound heterozygosity with the known severe alleles Arg178Ter or Asn425Asp (resulting in DTD) or with the mutation c.727-1G>C (causing mDTD). The 'Finnish mutation', c.-26+2T>C, and the p.Cys653Ser, both frequent mutations in non-Portuguese populations, were not identified in any of the patients of our cohort and are probably very rare in the Portuguese population. A targeted mutation analysis for p.Arg279Trp and p.Arg178Ter in the Portuguese population allows the identification of approximately 90% of the pathogenic alleles.

Influence of artificial accelerated aging on the color stability and opacity of composites of different shades.

AIM: The aim of this study was to evaluate the influence of artificial accelerated aging on the color stability and opacity of composites of different shades. METHODS: Four composites for direct use (Heliomolar, 4 Seasons, Tetric EvoCeram; QuiXfil) and one for indirect use (SR Adoro) in two shades were used: light (A2) and dark (C3 for direct, and D4 for indirect composite). QuiXfil was obtained in Universal shade. A Teflon matrix (12 X 2 mm) was used to obtain 54 specimens (N=6), which were submitted to color and opacity analysis (Spectrophotometer PCB 6807, Byk Gardner) before and after artificial accelerated aging for 384 hours. RESULTS: After the statistical analysis (2-way ANOVA - Bonferroni - P<0.05), significant color alteration was observed in the light and dark composites studied (P<0.05), with the exception of QuiXfil. Composite 4 Seasons/C3 showed less color alteration (ΔE=0.91). The opacity alteration (ΔOP) was higher for light composites. CONCLUSION: Artificial accelerated aging interfered in the optical properties assessed; however, the alterations seemed to be more related to the composites composition than to their shade.

Clinical and molecular diagnosis of the skeletal dysplasias associated with mutations in the gene encoding Fibroblast Growth Factor Receptor 3 (FGFR3) in Portugal.

Mutations in the gene that encodes Fibroblast Growth Factor Receptor 3 (FGFR3) are associated with Achondroplasia (MIM 100800), Hypochondroplasia (MIM 146000), Muenke Syndrome (MIM 602849), Thanatophoric Dysplasia (MIM 187600, MIM 187601) and Lacrimo-Auriculo-Dento-Digital Syndrome (MIM 149730).Here we report a clinical and molecular study in a large cohort of 125 Portuguese patients with these skeletal disorders. The identification of the P250R mutation allowed the confirmation of the Muenke Syndrome in 9 out of the 52 cases referred. Two known mutations were found in the Thanatophoric Dysplasia referred cases. No mutations were identified in the LADD syndrome patient. In Achondroplasia and Hypochondroplasia, genetic heterogeneity was present amongst the 70 clinically diagnosed patients with 5 different mutations identified. As in other studies, complex phenotypic heterogeneity amongst patients carrying the same gene defect was observed. In several cases, the new amino acids encoded, as a consequence of mutations, were related to the severity of patients' phenotype. The presence of 10 misdiagnosed cases emphasizes the importance of performing mutation analysis of the hotspot regions responsible for both dysplasias (Ach and Hch). For patients with an unquestionable clinical diagnosis, lacking the most common mutations, a complete screening of FGFR3 is necessary.

Physicochemical analysis of pasteurized human milk and commercial premature formulas fortified with phosphorus solution or commercial fortifier / Análise físico-química do leite humano pasteurizado e de fórmula comercial para prematuros suplementados com solução de fósforo ou fortificante comercial

A study was conducted to determine: the most appropriate proportion (1% or 10% v/v) of a phosphate solution (PS), containing 39mg/mL phosphorus, to be added to pasteurized human milk (HM) or commercial premature formula (FM); the final osmolality of such products, and whether precipitation occurs between calcium (Ca) and phosphorus (P) when commercial fortifier (FOR) or PS is added. A significant increase was observed in the concentrations of Ca in the samples of HM and FM containing FOR and a decrease in the samples of HM containing 10% (v/v) PS. The phosphorus levels increased significantly, in both HM and FM, when FOR or PS (1 and 10%) were added. Osmolality showed a significant increase in the solutions of HM with FOR or 10% PS added, and in the solution of FM containing 10% PS. Qualitative analysis of the precipitate formed on addition of 10% PS to FM revealed that it consisted of dicalcium phosphate. It was concluded that the addition of 10% PS to FM causes a fall in the Ca content, due to its precipitation with phosphate, promoting a reduction in the availability of both ions. On the other hand, the addition of 1% PS was demonstrated to cause no alteration in the Ca concentration, but a significant increase in P. These results suggest that the use of 1% PS is a potential means of supplementation of P after these patients are discharged.

Foi realizado um estudo para verificar: a concentração, 1 ou 10% (v/v), mais apropriada de solução de fósforo (SP), para ser adicionada nos produtos lácteos; a osmolalidade final de tais produtos suplementados; a ocorrência de precipitação entre o cálcio (Ca) e o fósfforo (P) com a adição de um fortificante comercial (FOR) ou SP. Verificou-se aumento significante nas concentrações de Ca nas amostras de leite materno pasteurizado (LM) e fórmula comercial (FL) contendo FOR e diminuição nas amostras de FL contendo 10% (v/v) de SP. Quanto aos níveis de fósforo, houve aumento significante tanto no LM quanto na FL, adicionados de FOR ou SP a 1 e 10%. Em relação à osmolalidade, houve aumento significante nas soluções de LM contendo FOR e de SP a 10% e na solução de FL a 10% de SP. A análise qualitativa do precipitado formado pela adição de 10% SP na FL revelou que o mesmo é constituído de fosfato bicálcico. Concluiu-se que a adição de SP na concentração de 10% em FL acarreta diminuição do Ca devido à precipitação do mesmo com o P, promovendo uma baixa na oferta de ambos os íons para o prematuro. Por outro lado, a adição de SP a 1% demonstrou que não houve diminuição dos níveis de Ca, mas aumento significante nos níveis de P. Estes resultados sugerem que o uso da SP a 1% é uma alternativa de suplementação de fósforo na alta hospitalar destes pacientes.

Pharmacokinetics of tramadol and o-desmethyltramadol in goats after intravenous and oral administration.

The aim of this trial was to implement a method to obtain a tool for analyses of tramadol and the main metabolite, o-desmethyltramadol (M1), in goat's plasma, and to evaluate the pharmacokinetics of these substances following intravenous (i.v.) and oral (p.o.) administration in female goats. The pharmacokinetics of tramadol and M1 were examined following i.v. or p.o. tramadol administration to six female goats (2 mg/kg). Average retention time was 5.13 min for tramadol and 2.42 min for M1. The calculated parameters for half-life, volume of distribution and total body clearance were 0.94+/-0.34 h, 2.48+/-0.58 L/kg and 2.18+/-0.23 L/kg/h following 2 mg/kg tramadol HCl administered intravenously. The systemic availability was 36.9+/-9.1% and half-life 2.67+/-0.54 h following tramadol 2 mg/kg p.o. M1 had a half-life of 2.89+/-0.43 h following i.v. administration of tramadol. Following p.o., M1 was not detectable.

Caracterização genética de seis plantéis comerciais de tilápia ( Oreochromis ) utilizando marcadores microssatélites / Genetic characterization of six commercial stocks of tilapia ( Oreochromis spp ) using microsatellite markers

Foram caracterizados geneticamente, utilizando-se cinco locos de microssatélites, 235 indivíduos de seis plantéis de tilápia (Ceará, Chitralada, Israel, Nilótica, Taiwan e Vermelha) da região Sudeste do Brasil. Verificou-se diferença genética entre os seis plantéis, obtida pelo cálculo do índice de fixação de alelos (Fst=0,3263). De modo geral, está ocorrendo perda de heterozigose nos plantéis, segundo mostrou a estimativa do coeficiente de endogamia intrapopulacional (Fis=0,0486). Os plantéis Israel e Nilótica foram os mais semelhantes geneticamente (Ig=0,6663). Os plantéis Chitralada e Taiwan foram os que menos apresentaram genes em comum (Ig=0,2463). O plantel denominado Vermelha foi o mais distinto entre todos.

Two hundred and thirty five individuals from six commercial stocks of tilapias (Ceará, Chitralada, Israel, Nilótica, Taiwan and Red) from the Southeastern region of the country were genetically characterized using five microsatellite loci. The results suggest large genetic difference among the stocks, estimated through the fixation allele index (Fst = 0.3263), and a considerable loss of heterozigosity accurs in most of the stocks, according to the population inbreeding coefficient (Fis=0.0486). The Israel and Nilótica stocks were genetically similar (Ig=0.6663), while Chitralada and Taiwan showed less genes in common (Ig=0.2463). The Red stock was the most distinct stock.

Pyoderma gangrenosum or leukaemia cutis?

We report a case of atypical bullous pyoderma gangrenosum associated with acute myeloid leukaemia in which we found atypical myeloid cells within the skin lesion. Although there have been many reported cases of leukaemia-associated pyoderma gangrenosum, the finding of myeloblasts in the skin has rarely been described.

Common germinal-center B-cell origin of the malignant cells in two composite lymphomas, involving classical Hodgkin's disease and either follicular lymphoma or B-CLL.

BACKGROUND: Classical Hodgkin's disease (HD) and B-cell non-Hodgkin lymphoma (NHL) occasionally occur in the same patient. Such composite lymphomas represent interesting models to study the pathogenesis of B-cell lymphomas and the relationship between HD and B-cell NHL. MATERIALS AND METHODS: We analyzed two composite lymphomas (a combination of classical HD with follicular lymphoma [FL] and a combination of classical HD with B-cell chronic lymphocytic leukemia [B-CLL]) by micromanipulation of single cells from tissue sections and amplification of immunoglobulin V region genes for the clonal relationship of the tumor cells. RESULTS: In both cases, clonally related variable (V) genes with both shared as well as distinct somatic mutations were obtained from the two lymphomas, showing that in each of the cases the distinct tumor cells were members of a common germinal center (GC) B-cell clone. FL cells from two different lymph nodes of patient 1 showed a similar mutation pattern, suggesting that infiltration of these lymph nodes by tumor cells was not restricted to a particular FL cell or subclone. In the FL, a single cell was identified with a mutation signature indicating that premalignant cells can persist in the tissue. CONCLUSIONS: The cases presented here further underline the close relationship between HD and B-cell NHL and the role of the GC in lymphomagenesis. Whereas the latter was already suggested for FL and HD, the present study indicates that also in the B-CLL subset characterized by mutated Ig genes, important steps in malignant transformation happen in the GC, and that HRS cells can derive from CD5-positive B cells.

Does prolonged cyanide exposure have a diabetogenic effect?

Cyanide exposure through cassava consumption has been associated with the development of malnutrition-related diabetes mellitus (MRDM). However, there are few experimental reproductions of this disease. In the present study 42 rats received 0, 9.0 or 12.0 mg KCN/kg bw/d for 15 d, 26 pigs were dosed with 0, 2.0, 4.0 or 6.0 mg KCN/kg for 74 d, and 34 goats received 0, 0.3, 0.6, 1.2 or 3.0 mg KCN/kg for 5 mo. At the end of each experimental period, plasma samples were obtained for glucose and thiocyanate measurement, and the pancreas was collected for histopathologic study. No significant differences in plasma glucose concentrations occurred between groups. The pancreas had no pathology. Chronic cyanide exposure did not promote diabetogenic effects in rats, swine or goats, suggesting that cyanide is not responsible for MRDM in humans.

The gene conversion hypothesis of MHC evolution: a review.

Gene conversion is often invoked to explain the evolution of sequence patterns observed in major histocompatibility complex (MHC) genes and their alleles. This is the gene conversion hypothesis of MHC sequence evolution. These observations and their interpretation probably belong in a larger theoretical framework, namely the evolution of systems of resistance to rapidly evolving pathogens. This review looks critically at the evidence in favor of the gene conversion hypothesis in this context. We conclude that the case for the existence of an adaptive mechanism in the MHC favoring gene conversion mutations is not proven.

Insertion of the 5' part of BCR within the ABL gene at 9q34 in a Philadelphia-negative chronic myeloid leukemia.

We report a chronic myeloid leukemia patient without evidence of a Philadelphia (Ph) chromosome in whom RT-PCR analysis performed in blast crisis demonstrated the existence of both common b3a2 and b2a2 BCR/ABL fusion transcripts. In situ hybridization studies with BCR- and ABL-specific probes showed location of the BCR/ABL fusion gene on chromosome 9, band q34, instead of at chromosome 22q11, and that it resulted from an insertion of the 5' side of BCR within the ABL gene on chromosome 9. The vast majority of cells showed a BCR/ABL fusion gene on both chromosomes 9, which is equivalent to a double Ph chromosome, thus reinforcing the notion that the critical event in CML is the formation of a functional BCR/ABL fusion gene.