Abstract: Objective To identify a rare mutation (GCC-GAC) at codon 27 exon1 of β-globin gene in a β-thalassemia carriers from a Chinese family. Methods Used hematological cytoanalyzer and electrophoretic analysis system to analysis the phenotype. Gap-PCR was used to detect known mutation of α-globin gene. Known mutation of β-globin gene was detected by reverse dot blot analysis. The sequence of β-globin gene was performed to identify the genotype and to find out the underlying mutation of the sample. Results The proband presented a typical β-thalassemia intermedia phenotype, and the HbF was 5.8%，and no abnormal parameter were found in other family members. No known mutation was detected. The sequencing revealed heterozygosity of codon 2(CAT-CAC) in the proband and her mother; and codon 27 (GCC-GAC) mutation heterozygosity at exon1 CD27 (GCC-GAC) （Ala-Asp）of β-globin gene in the proband only. Conclusions A rare mutation at exon1 which may lead to β-thalassemia in Chinese population was found. The finding may enrich knowledge of the screening in β-thalassemia as well as the genetic counseling and Clinical diagnosis.

Key words: β-thalassemia, gene mutation, β-globin gene