Misdiagnosis of ß-Thalassemia Major Due to Chinese Gγ+(Aγδß)0-Thalassemia Combined with ß0-Thalassemia.

ABSTRACT

δß-thalassemia is a rare type of thalassemia characterized by increased Hb F levels, including mainly Chinese Gγ(Aγδß)0-thalassemia, Yunnanese Gγ(Aγδß)0-thalassemia, Cantonese Gγ(Aγδß)0-thalassemia in China. Due to the low rate of δß-thalassemia carriers, there are few reports of δß-thalassemia combined with ß-thalassemia causing ß-thalassemia major. Herein, we described the combination of Chinese Gγ(Aγδß)0-thalassemia and ß-thalassemia leading to ß-thalassemia major in a Chinese patient. Hemoglobin analysis was performed by capillary electrophoresis (CE). Routine genetic analysis was carried out by gap-polymerase chain reaction (Gap-PCR) and PCR and reverse dot blot (PCR-RDB). Multiple ligation-dependent probe amplification (MLPA) was used to detect the large deletion, and Gap-PCR confirmed the deletion. A CE result showed an elevated Hb F level of 98.7% and 11.7% in the proband and her mother, but the proband was diagnosed with ßCD17M/ßCD17M using routine genetic analysis. However, her father was heterozygous for CD17 in ß-globin, and her mother was detected as SEA heterozygous. The further analysis presented that the proband had actually missed the diagnosis of Chinese Gγ(Aγδß)0-thalassemia by MLPA and PCR-RDB. Finally, the genotype of the proband was corrected from ßCD17M/ßCD17M to ßCD17M/ßGγ(Aγδß)0. This is the first report of Chinese Gγ(Aγδß)0-thalassemia combined with ß-thalassemia resulting in ß-thalassemia major in China. Screening for δß-thalassemia by Hb analysis could be an effective method.