ABSTRACT
Objectives The quantitation of BCR-ABL1 mRNA is mandatory for chronic myeloid leukemia (CML) patients, and RT-qPCR is the most extensively used method in testing laboratories worldwide. Nevertheless, substantial variation in RT-qPCR results makes inter-laboratory comparability hard. To facilitate inter-laboratory comparative assessment, an international scale (IS) for BCR-ABL1 was proposed. Methods The laboratory-specific conversion factor (CF) to the IS can be derived from the World Health Organization (WHO) genetic reference panel; however, this material is limited to the manufacturers to produce and calibrate secondary reference reagents. Therefore, we developed secondary reference calibrators, as lyophilized cellular material, aligned to the IS. Our purpose was both to re-evaluate the CF in 18 previously harmonized laboratories and to propagate the IS to new laboratories. Results Our field trial including 30 laboratories across Latin America showed that, after correction of raw BCR-ABL1/ABL1 ratios using CF, the relative mean bias was significantly reduced. We also performed a follow-up of participating laboratories by annually revalidating the process; our results support the need for continuous revalidation of CFs. All participating laboratories also received a calibrator to determine the limit of quantification (LOQ); 90% of them could reproducibly detect BCR-ABL1, indicating that these laboratories can report a consistent deep molecular response. In addition, aiming to investigate the variability of BCR-ABL1 measurements across different RNA inputs, we calculated PCR efficiency for each individual assay by using different amounts of RNA. Conclusions In conclusion, for the first time in Latin America, we have successfully organized a harmonization platform for BCR-ABL1 measurement that could be of immediate clinical benefit for monitoring the molecular response of patients in low-resource regions.
Subject(s)
Fusion Proteins, bcr-abl/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Calibration , Humans , Latin America , Quality Control , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction/methods , Reference Standards , Reproducibility of ResultsABSTRACT
Phelan McDermid Syndrome is caused by the loss of genetic material in a chromosome from pair 22, at the band q13.3. We describe five patients with deletion 22q13.3 in order to establish a genotype-phenotype association, and report the first case described in conjoined twins. We analyzed the perinatal history, psychomotor behavior, language, and the presence of minor dysmorphism. Karyotypes and in situ hibridization (FISH) for critical region 22q13.3 were performed to all patients. There were hypotonia, developmental delay, and delay or absence of language. A 22q13.3 deletion was detected in all patients described, two cases had a deletion and the other three had a ring of chromosome 22, one in a pure cell line, while the twins presented mosaicism. Karyotype and FISH for 22q11.2 critical region should be performed, with 22q13.3 control probe to detect the deletion of Phelan McDermid syndrome in all patients with clinical phenotype suggestive and evocative of velo-cardio-facial syndrome.
Subject(s)
Chromosome Disorders/diagnosis , Chromosome Disorders/genetics , Diseases in Twins/diagnosis , Diseases in Twins/genetics , Twins, Conjoined , Adolescent , Child , Child, Preschool , Chromosome Deletion , Chromosomes, Human, Pair 22/genetics , Female , Genotype , Humans , Karyotyping , Male , PhenotypeABSTRACT
El síndrome de Phelan McDermid es producido por una pérdida de material genético, en un cromosoma del par 22, a nivel de la banda q13.3. Se describieron cinco pacientes con deleción 22q13.3 para correlacionar genotipo-fenotipo y comunicar el primer caso descripto en gemelas siamesas. Se registraron antecedentes perinatales, psicomotores, conducta, lenguaje y presencia de dismorfas. Se realizó cariotipo e hibridación in situ fuorescente (FISH) para región crítica 22q13.3. Presentaron hipotonía, dismorfas menores, retraso madurativo y retraso o ausencia del lenguaje. Se confrmó deleción 22q13.3 en los cinco pacientes, encontrándose una deleción en dos casos y un anillo del cromosoma 22 en tres, siendo uno con línea pura, y las siamesas, con mosaicismo, con una línea celular normal. En pacientes con clínica sugestiva y fenotipo evocador de síndrome velo-cardio-facial, se debe realizar cariotipo y FISH para región crítica 22q11.2 con sonda control 22q13.3, para detectar la deleción del Síndrome de Phelan McDermid.
Phelan McDermid Syndrome is caused by the loss of genetic material in a chromosome from pair 22, at the band q13.3. We describe fve patients with deletion 22q13.3 in order to establish a genotype-phenotype association, and report the frst case described in conjoined twins. We analyzed the perinatal history, psychomotor behavior, language, and the presence of minor dysmorphism. Karyotypes and in situ hibridization (FISH) for critical region 22q13.3 were performed to all patients. There were hypotonia, developmental delay, and delay or absence of language. A 22q13.3 deletion was detected in all patients described, two cases had a deletion and the other three had a ring of chromosome 22, one in a pure cell line, while the twins presented mosaicism. Karyotype and FISH for 22q11.2 critical region should be performed, with 22q13.3 control probe to detect the deletion of Phelan McDermid syndrome in all patients with clinical phenotype suggestive and evocative of velo-cardio-facial syndrome.
Subject(s)
Adolescent , Child , Child, Preschool , Female , Humans , Male , Chromosome Disorders/diagnosis , Chromosome Disorders/genetics , Diseases in Twins/diagnosis , Diseases in Twins/genetics , Twins, Conjoined , Chromosome Deletion , /genetics , Genotype , Karyotyping , PhenotypeABSTRACT
El síndrome de Phelan McDermid es producido por una pérdida de material genético, en un cromosoma del par 22, a nivel de la banda q13.3. Se describieron cinco pacientes con deleción 22q13.3 para correlacionar genotipo-fenotipo y comunicar el primer caso descripto en gemelas siamesas. Se registraron antecedentes perinatales, psicomotores, conducta, lenguaje y presencia de dismorfas. Se realizó cariotipo e hibridación in situ fuorescente (FISH) para región crítica 22q13.3. Presentaron hipotonía, dismorfas menores, retraso madurativo y retraso o ausencia del lenguaje. Se confrmó deleción 22q13.3 en los cinco pacientes, encontrándose una deleción en dos casos y un anillo del cromosoma 22 en tres, siendo uno con línea pura, y las siamesas, con mosaicismo, con una línea celular normal. En pacientes con clínica sugestiva y fenotipo evocador de síndrome velo-cardio-facial, se debe realizar cariotipo y FISH para región crítica 22q11.2 con sonda control 22q13.3, para detectar la deleción del Síndrome de Phelan McDermid.(AU)
Phelan McDermid Syndrome is caused by the loss of genetic material in a chromosome from pair 22, at the band q13.3. We describe fve patients with deletion 22q13.3 in order to establish a genotype-phenotype association, and report the frst case described in conjoined twins. We analyzed the perinatal history, psychomotor behavior, language, and the presence of minor dysmorphism. Karyotypes and in situ hibridization (FISH) for critical region 22q13.3 were performed to all patients. There were hypotonia, developmental delay, and delay or absence of language. A 22q13.3 deletion was detected in all patients described, two cases had a deletion and the other three had a ring of chromosome 22, one in a pure cell line, while the twins presented mosaicism. Karyotype and FISH for 22q11.2 critical region should be performed, with 22q13.3 control probe to detect the deletion of Phelan McDermid syndrome in all patients with clinical phenotype suggestive and evocative of velo-cardio-facial syndrome.(AU)
ABSTRACT
El síndrome de Phelan McDermid es producido por una pérdida de material genético, en un cromosoma del par 22, a nivel de la banda q13.3. Se describieron cinco pacientes con deleción 22q13.3 para correlacionar genotipo-fenotipo y comunicar el primer caso descripto en gemelas siamesas. Se registraron antecedentes perinatales, psicomotores, conducta, lenguaje y presencia de dismorfas. Se realizó cariotipo e hibridación in situ fuorescente (FISH) para región crítica 22q13.3. Presentaron hipotonía, dismorfas menores, retraso madurativo y retraso o ausencia del lenguaje. Se confrmó deleción 22q13.3 en los cinco pacientes, encontrándose una deleción en dos casos y un anillo del cromosoma 22 en tres, siendo uno con línea pura, y las siamesas, con mosaicismo, con una línea celular normal. En pacientes con clínica sugestiva y fenotipo evocador de síndrome velo-cardio-facial, se debe realizar cariotipo y FISH para región crítica 22q11.2 con sonda control 22q13.3, para detectar la deleción del Síndrome de Phelan McDermid.(AU)
Phelan McDermid Syndrome is caused by the loss of genetic material in a chromosome from pair 22, at the band q13.3. We describe fve patients with deletion 22q13.3 in order to establish a genotype-phenotype association, and report the frst case described in conjoined twins. We analyzed the perinatal history, psychomotor behavior, language, and the presence of minor dysmorphism. Karyotypes and in situ hibridization (FISH) for critical region 22q13.3 were performed to all patients. There were hypotonia, developmental delay, and delay or absence of language. A 22q13.3 deletion was detected in all patients described, two cases had a deletion and the other three had a ring of chromosome 22, one in a pure cell line, while the twins presented mosaicism. Karyotype and FISH for 22q11.2 critical region should be performed, with 22q13.3 control probe to detect the deletion of Phelan McDermid syndrome in all patients with clinical phenotype suggestive and evocative of velo-cardio-facial syndrome.(AU)
