Mutations in noncoding sequences of the promoter region

Mutations in the noncoding sequences of the
promoter region at the 5! end of the !-globin
cluster (on the 5! side of the #-globin genes) can
also lead to hereditary persistence of fetal
hemoglobin. Although the highly conserved
sequences CACCC, CCAAT, or ATAAA are not affected,
the number of observed mutations substantiates
the significance of the remaining
noncoding sequences (long-range transcription
control). They are probably required for the
changes in transcription control of the different
gene loci that occur during embryonic and fetal
development.