[Molecular diagnosis for a novel deletion mutation of α thalassemia].

[alpha-thalassemia]

To raise awareness of the pathogenesis and diagnosis of thalassemia by reporting one case of α thalassemia patient with a large deletion fragment and analyzing the pedigree .Firstly , blood cells and hemoglobin electrophoresis analysis were used for screening of thalassemia , and then three common kinds of deletional α thalassemia in Chinese was detected by Gap -PCR , three common kinds of non- deletional α thalassemia and seventeen common mutations of β thalassemia in Chinese were analyzed by using PCR- RDB . The unknown mutation of samples was identified with Multiplex Ligation-dependent Probe Amplification (MLPA ) and DNA sequencing .The proband female presented with microcytic hypochromic anemia (hemoglobin 71 g /L , mean corpuscular volume 52 .4 fl , mean corpuscular hemoglobin 16 .1 pg ), and hemoglobin A 2 1 .4 %. The identified large deletion fragment length was 21 925 bp , so far which had not been reported in the world and was named -α ²¹ ·⁹ . It was registered in USA DNA database and GenBank accession number as KF 360979 . The genotype of her mother and father and brother were αα /-α ²¹ ·⁹ , --(SEA )/-α ³ ·⁷ , αα /-α ³ ·⁷ respectively , and the genotype of her and her sister were the same of --(SEA )/-α ²¹ ·⁹ . Her husband gene of thalassemia had no mutation , so prenatal diagnosis of thalassemia was not carried out in the pregnant woman .The discovery of -α (21 .9 ) deletion mutation was enriched the DNA mutation gene database of thalassemia , and had important significance for genetic counseling and thalassemia prenatal diagnosis .

Diseases
Validation

Diseases presenting "hypochromic anemia" symptom

alpha-thalassemia

erythropoietic protoporphyria

This symptom has already been validated