Abstract
Background : Non-deletional hemoglobin (Hb) H disease is the severest form of α- thalassemia ( thal ) compatible with post-natal life, which is caused by the interaction of an α-globin gene mutation with α 0 -thal. Therefore, it is important to identify rare α-globin gene mutations for the prevention of severe form of non-deletional Hb H disease . Methods: In all, 61,796 samples were characterized at our center. Common α- and β- thalassemia mutations were detected by routine DNA analysis (gap-PCR and PCR-RDB ). The DNA sequencing of α-globin genes was performed to identify the unknown mutation. Statistical analyses were conducted using SPSS 19.0 statistical software. Results: Of the 61,796 samples, eight were identified as α2 codon 30 (-GAG) ( HBA2 : c.91_93delGAG) mutation s, and of these, four had coinheritance with - - SEA deletion Patients with the heterozygous α2 codon 30 (-GAG) ( HBA2 : c.91_93delGAG) mutation had significantly lower levels of MCV and MCH than healthy individuals ( p < 0.01), and coinheritance with - - SEA deletion aggravated the α-thal phenotype , associated with severe Hb H disease . Moreover, a significant difference in the clinical severity was found in the Hb H disease patients with the same genotype.Conclusions: This finding is of great significance for clinicians to provide accurate genetic counseling , particularly prenatal diagnosis and establish a rigorous diagnostic procedure .
Prenatal diagnosis of a rare
β
‐thalassemia gene －90 (C>T) (
HBB
: c.‐140 C>T) mutation associated with deletional Hb H disease (‐‐
SEA
/‐
α
4.2
)
