Abstract
Cytogenetic abnormalities have important implications in the diagnosis and prognosis of acute leukemia. Karyotype guides physicians to plan appropriate management strategies and diagnoses for their patients. Cytogenetic analysis was made for all cases using the trypsin-Giemsa banding technique. A normal karyotype was present in 51.2% (n=65) of the cases whereas 48.8% (n=62) had an abnormal karyotype. Most of the abnormal cases showed hyperdiploidy (13.4%). This study revealed a relative lack of good prognostic cytogenetic aberrations in Pakistani children with ALL. Most of the abnormal cases showed hyperdiploidy (13.4%).
Introduction
Acute lymphoblastic leukemia (ALL) accounts for 75-80% of childhood leukemias and various subtypes can be defined based on cell morphology, immunophenotype, karyotype, and gene expression characteristics. Cytogenetic analysis plays a significant role in understanding the pathophysiology as well as clinical behavior of the condition. This study aimed in determining the cytogenetic profile of Pakistani children with ALL to provide the prognosis and hence proper management of these patients.
Materials and Methods
All patients diagnosed with acute lymphoid leukemia (ALL) who were <15 years of age were included in the analysis. All cases of acute myeloid leukemia and undifferentiated leukemia were excluded. Chromosomal abnormalities were identified and described according to the International System for Human Cytogenetic Nomenclature (ISCN) and results were expressed. Counseling regarding the prognostic impact of the detected abnormality was taken from parents of all children before collecting bone marrow samples.
Results
A total of 153 children were diagnosed with the all-male syndrome (ALL) in the UK, with more male than female patients (M:F 1.8:1). The cytogenetic analysis couldn't be performed in n=26 (16.9%). Out of the total (n=127) successfully completed samples, 51.2% had a normal karyotype. In n=65 samples, various cytogenetic abnormalities were detected.
Aneuploidies
· Hyperdiploidy (47-57 chromosomes) was identified in (n=17, 13.4%).
· Near-triploidy (58-80 chromosomes) and near-tetraploidy (81-103 chromosome) was detected in five (3.9%) and one patients (0.8%).
· There was a single case with 28 chromosomes (hyperhaploidy).
Translocations
· Nine (7.1%) patients were identified to harbor t(9;22)(q34;q11.2)
· Two (1.6%) patients had t(1;19)(q25;p13.3).
· Seven other translocations which were present in seven different patients included t(1;7) (p34.3;q36), t(2;6)(q21.3;q27), t(2;9)(q33;p13), t(5;9) (q13;p24), t(2;14)(p11.2;q32), t(9;14)(p24;q11.2) and t(9;17)(p12;q11.2).
Discussion
The male to female ratio was found to be 1.8:1 in this study. Hyperdiploidy (47-57 chromosomes) was detected in 13.4% of patients (n=17) whereas the usual prevalence of this abnormality as reported in the literature is around 25%. Surprisingly, t(12;21) (p13;q22) which is the commonest translocation in children with ALL and carries a good prognosis was not found in the Pakistani population.
Conclusion
The study shows a relative lack of good prognostic abnormalities like t(12;21) (p13;q22) and hyperdiploidy (47-57 chromosomes) in Pakistani children with ALL. The prevalence of poor prognostic cytogenetic aberrations like t(9;22)(q34;q11.2) is comparable to available international literature.
References
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