Duplication of the der(14) chromosome of a translocation (8;14) in a case of Burkitt's type L3-ALL

Current status of the genetic susceptibility in attenuated adenomatous polyposis

Adenomatous polyposis (AP) is classified according to cumulative adenoma number in classical AP (CAP) and attenuated AP (AAP). Genetic susceptibility is the major risk factor in CAP due to mutations in the known high predisposition genes APC and MUTYH. However, the contribution of genetic susceptibility to AAP is lower and less understood. New predisposition genes have been recently proposed, and some of them have been validated, but their scarcity hinders accurate risk estimations and prevalence calculations. AAP is a heterogeneous condition in terms of severity, clinical features and heritability. Therefore, clinicians do not have strong discriminating criteria for the recommendation of the genetic study of known predisposition genes, and the detection rate is low. Elucidation and knowledge of new AAP high predisposition genes are of great importance to offer accurate genetic counseling to the patient and family members. This review aims to update the genetic knowledge of AAP, and to expound the difficulties involved in the genetic analysis of a highly heterogeneous condition such as AAP.

Masked Philadelphia chromosome due to atypical BCR/ABL localization on the 9q34 band and duplication of the der(9) in a case of chronic myelogenous leukemia

The cytogenetic studies and molecular evaluation of a Philadelphia chromosome negative chronic myelogenous leukemia patient with trisomy 21 (100% metaphases) and trisomy 9 (50% metaphases) at diagnosis are described. Fluorescence in situ hybridization revealed an atypical location of the BCR/ABL fusion signal on 9q, which was duplicated in cells with trisomy 9 simulating a double Ph. The patient was successfully treated with Glivec (also known as Gleevec; Novartis, Basel, Switzerland) and achieved complete hematological and cytogenetic response as well as a reduction of BCR/ABL transcripts detected by real-time quantitative PCR.

Burkitt lymphoma with a duplication of der(8)t(2;8). Interpretation of a complex karyotype by chromosome painting

A 51-year-old male patient was diagnosed with Burkitt lymphoma 3 months after cardiac transplantation. The bone marrow karyotype was very complex, and to better define the complex karyotype we used the in situ suppression hybridization technique. Previously we interpreted this karyotype to be: 48,XY,t(2;8)(p11;q24), +der(2)t(2;8)(p11;q24),del(2)(q23), +7, +der(8)t(2;8)(p11;q24), +12, -13, -18, by G banding techniques, with a duplication of the t(2;8) derivatives. After in situ hybridization we changed to a: 48,XY,t(2;8)(p11;q24),t(2;18)(q23;q22), +7, +der(8)t(2;8)(p11;q24), +12, -13, which implies duplication of only one t(2;8) derivative.