Genetic abnormalities are found in 50% of cases of chronic lymphocytic leukaemia (CLL) by
cytogenetic analysis and in a higher percentage of patients using molecular techniques. The
commonest cytogenetic abnormalities are trisomy 12 and deletions or translocations of the
long arm of chromosome 13 usually involving band q14. The genetic consequences of
trisomy 12 are unknown but structural abnormalities of chromosome 13814 frequently
involve hetero or homozygous loss of a region distal to the retinoblastoma gene which may …