PCR detection of thalassemia

Thalassemia (Thalassemia) is a hereditary chronic hemolytic anemia, which is a common single-gene genetic disease with a high incidence rate in the world. The incidence is higher in Guangdong and Guangxi, Guizhou, Sichuan and other places, and as high as 15% in Guangxi and other places. Thalassemia is due to the imbalance of globin caused by gene mutation, which reduces the synthesis of peptide chains with normal structure or even does not synthesize it as hemolytic anemia. The types of genes involved in acceptability are divided into α, β, γ, etc. Among them, α and β-thalassemia are the most common and cause great harm. The globin gene cluster is located on the short arm of human No. 6 staining, and there are two repetitive genes located in α1, α2, two α genes and their flanking sequences, which have great homology, and are prone to unequal exchange of chromosomes, resulting in α Gene deletion - alpha thalassemia. The partial deletion of α-thalassemia gene includes partial deletion of α1 gene, deletion of α2 gene, simultaneous deletion of α1 and α2 genes and non-deletion thalassaemia. PCR technology can be used to amplify the α1 and α2 genes to detect whether these genes are missing, mutated, etc., so as to diagnose α-thalassemia. β-thalassemia gene defects are mainly manifested as single nucleotide mutations in the gene sequence, or deletions and insertions of a few bases, which reduce or delete the normal β-globin peptide chain synthesis. The diagnosis can be made by spot hybridization of PCR products using site-specific oligonucleotide probes (Aso).

Phenylketonuria

Phenylketonuria (PKU) is an autosomal recessive genetic disease in which phenylpropionate hydroxylase converts tyrosine into tyrosine, resulting in massive accumulation of phenylalanine and its metabolites in the body, resulting in brain damage and Irreversible intellectual disability. PKU patients are normal at birth. Once the neonates are diagnosed with PKU and stop breastfeeding, the low-phenylalanine diet therapy can be used for 8-10 years, which can maintain the normal development of the patient's intelligence level. Because low-phenylalanine diet is very expensive and unaffordable for ordinary families, it is a good choice to implement prenatal diagnosis to prevent the birth of children. PAH is only expressed in hepatocytes, and cannot be used for enzymatic activity analysis of blood cells, fibroblasts, amniotic fluid, and villous cells, but only for genetic diagnosis. The genetic change of PKU is not the deletion of all PAH genes, but the main manifestation is point mutation, and there are many mutation sites. The use of PCR amplification combined, ASO, SSCP or the use of amplified fragment length polymorphism analysis (AmpFLA) for detection, these techniques are more complex, the inspection personnel must be professionally trained.