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Cytogenetics investigation in childhood chronic myeloid leukemia
D Chinnappan1, I C Verma, V P Choudhry
1Center for Human Genetics, University School of Medicine, Boston, MA 02118, USA.
Insights
Cytogenetic analysis revealed chromosomal abnormalities in 19 of 30 children with chronic myeloid leukemia (CML). The Philadelphia chromosome translocation t(9; 22) was common in adult-type CML, while juvenile-type CML often presented with normal karyotypes.
Area of Science:
- Hematology
- Cytogenetics
- Pediatric Oncology
Background:
- Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the Philadelphia chromosome.
- Distinguishing between adult-type CML (ACML) and juvenile-type CML (JCML) in children is crucial for prognosis and treatment.
- Cytogenetic analysis plays a vital role in diagnosing and classifying CML.
Purpose of the Study:
- To investigate the spectrum of cytogenetic abnormalities in pediatric CML.
- To compare chromosomal findings between ACML and JCML in children.
- To assess the diagnostic utility of cytogenetics in pediatric CML.
Main Methods:
- Peripheral blood samples from 30 children diagnosed with CML were analyzed.
- Cytogenetic investigations included karyotyping and Philadelphia chromosome detection (t(9; 22)).
- Nucleolar Organizer Region (NOR) activity was assessed in a subset of patients.
Main Results:
- Chromosomal abnormalities were detected in 19 out of 30 pediatric CML patients.
- The classical Philadelphia chromosome translocation t(9; 22) was found in 88.9% of ACML patients.
- JCML patients predominantly showed normal karyotypes, with rare instances of monosomy 8 and 21q deletion.
- Reduced NOR activity was observed in a significant proportion of ACML patients compared to controls.
- Variant translocations, such as t(9; 13; 22), and monosomy B were identified in ACML and JCML, respectively.
- Cytogenetic studies aided in the diagnosis of CML in two ACML cases.
Conclusions:
- Cytogenetic analysis is essential for characterizing pediatric CML, revealing distinct patterns between ACML and JCML.
- The Philadelphia chromosome is a hallmark of ACML, while JCML often presents with a normal karyotype.
- Cytogenetic findings can assist in the diagnosis and classification of CML in children.
Abstract:
Cytogenetics investigations, mostly from peripheral blood, were carried out in 30 children with CML. Amongst a sample of 30 patients, 18 had chronic myeloid leukemia of adult variety (ACML), while the remaining 12 children had the juvenile type of chronic myeloid leukemia (JCML). Sixteen (88.9%) out of the 18 patients suffering from ACML tested positive for the classical Philadelphia chromosome translocation t(9; 22). Of the remaining two ACML patients, one tested positive for t(9; 13; 22) while no visible chromosomal changes were observed in the other patient. The activity of Nucleolar Organizer Region (NOR) was significantly reduced in 11 (61.1%) of the 18 patients suffering from ACML, when compared to that of 21 normal healthy controls. Ten out of the 12 patients suffering from JCML had normal karyotypes, while monosomy 8 and 21 q deletion were seen in the remaining two patients respectively. Amongst the 30 CML patients, chromosomal abnormalities were observed in 19 patients. Variant Philadelphia chromosome translocation (9; 13; 22) and monosomy B were observed in ACML and JCML, respectively. In two ACML patients, cytogenetic studies were helpful in diagnosis of the disease.