Acute leukaemia

Question 1

Duplications that cause lead to AML

Answer 1

 Trisomy 8 and Trisomy 21 (gives a predisposition to AML  as seen in TAM in Down’s syndrome)

Question 2

Inversion or translocations leading to AML

Answer 2

• Acute Myeloid Leukaemia / AML; t (8; 21)  RUNX1+RUNX1T1
15% of AML
o Partial block – some mature cells remain

• Core Binding Factor – AML / CBF-AML; Inv (16), t (16; 16)  fusion gene
12% of AML
o Partial block – some mature ‘eosinophil-type’ cells remain

• Acute Promyelocytic Leukaemia / APML; t (15; 17)  PML-RARA
APML

Question 3

Chromosome loss and part-deletion causing AML

Answer 3

 MOST COMMON = del (5q) or del (7q)

 Leukaemogenesis from…
• Due to loss of tumour suppressor gene
• One copy of an allele may be insufficient for normal haemopoiesis
• Possible loss of DNA repair systems