'Silent' beta-thalassaemia caused by a 'silent' beta-chain mutant: the pathogenesis of a syndrome of thalassaemia intermedia.

In a Greek family three cases of beta-thalassaemia intermedia were diagnosed as resulting from the interaction of a typical high HbA2-beta-thalassaemia with an atypical (silent) beta-thalassaemia gene. Following electrophoresis of globins on an acid-urea-Triton-acrylamide system, an otherwise silent beta-like variant was revealed in the carriers of the atypical thalassaemia gene and in the intermediates; it amounted to 33% of the non-alpha chains in the former and to c. 75% in the latter. The provisional name Hb Knossos is suggested for this abnormality.