[Genotypes of 1 571 cases of Hb H disease in Guangxi area]

To analyze the status and genotypes of Hb H disease in GuangXi area.

Human genomic DNA of 50 377 suspected thalassemia patients was extracted from blood, amniotic fluid and chorionic villi by beads. The deletion of α-thalassemia was detected by Gap-PCR, and the gene mutation of α or β-thalassemia was detected by PCR- RDB. Performing multiplex ligationdependent probe amplification detection and gene sequencing in α or β-globin for the specimens in question.

There were 1 571 Hb H disease patients in total from 2011 to 2013, and the detection rates were 2.82%, 3.54% and 3.00% respectively. The vast majority of patients had the Southeast Asian deletion (--(SEA)) on one allele. The - α³·⁷ (rightward) deletion was the most common on the other allele, followed by Hb Constant Spring (Hb CS), the -α(4.2) (leftward) deletion, Hb Westmead (Hb WS) and Hb Quong Sze (Hb QS) mutations. There were 33 Hb H disease patients which genotypes was α(CS)α/α (CS)α. Five patients had THAI deletion(--(THAI)) with deletion or point mutation of α-thalassemia. 95 patients had concomitant β-thalassemia (β-thal) heterozygosity. Tere was a novel genotype of --(SEA)/-α²¹·⁹ causing Hb H disease.

GuangXi area had a high accidence of Hb H disease, the results reflected the genetic diversity and genetic heterogeneity of Hb H disease, the latter may also occur new mutations or combined β-thalassemia, some effective measures should be taken to strengthen screening efforts to prevent underdiagnosis of Hb H disease.