Compound heterozygosity for a rare small deletion and a common point mutation in the beta-globin gene: report of two Chinese families.

摘要

INTRODUCTION: Most cases of beta-thalassemia are caused by point mutations in the beta-globin gene. Only a minority of beta-thalassemia mutations are small deletions in the exons of the beta-globin gene. METHODS: Here, we report two cases of beta-thalassemia that were caused by compound heterozygosity for a rare small deletion and a common point mutation. RESULTS: Patient A carried a rare 14-bp deletion (CD89-93) mutation plus the common mutation -28(A>G). Patient B carried a rare 13-bp deletion (CD54-58) plus the common mutation IVS-2-654(C>T). CONCLUSION: Patient B is the second report of the CD54-58(-13 bp) deletion. However, our report differs from the previous report in two ways: we performed a family study based on multiple samples; and the carriers and patient showed an elevated level of HbF, which was not observed in the previous case.