Occurrence of haemoglobin Norfolk (alpha2 57 (E6) Gly leads to Asp beta2) at the level of 33% in an Italian family from Calabria.

An abnormal, fast-moving haemoglobin was observed in 5 healthy subjects of a family from Calabria (southern Italy). In all these carriers the abnormal haemoglobin, which structural studies identified as Hb Norfolk (alpha2 57 (E6) Gly leads to Asp beta2) [4], occurs at a level averaging 33% of the total haemoglobin. Biosynthetic studies showed no evidence for unbalance of the globin chain synthetic ratio. In order to account for the observed percentages of Hb Norfolk, current concepts about the alpha-globin chain genetic system are reviewed, and different genic arrangements which would be in agreement with the experimental findings are discussed.