[The application of multiplex ligation-dependent probe amplification technology in diagnosis and prenatal diagnosis of α-thalassemia].

OBJECTIVE

To investigate the multiplex ligation-dependent probe amplification (MLPA) technology in the detection of gene deletion and prenatal diagnosis of α-thalassaemia.

METHODS

Phenotypes were analyzed by whole blood cell counting and hemoglobin component detection of peripheral blood samples from the subjects. The gene deletions and point mutations of α- thalassaemia were detected with regular gap-PCR and reverse dot blot (RDB) method. At last, the MLPA method was applied for detection of α-globin gene deletion. All the prenatal diagnosis samples were detected with both gap-PCR and MLPA method.

RESULTS

α-thalassaemia phenotype was found in 75 samples from 1256 (628 couples) peripheral blood samples for pre-pregnancy or prenatal thalassemia gene screening. Among them, 71 samples carrying α-gene mutations and consistent with phenotypes were detected by routine methods. In the other 3 samples with no α-gene mutations detected and 1 sample with HbH phenotype but genotype of ﹣α(4.2)/αα were analyzed by MLPA and found each one samples of whole α-globin gene cluster deletion, respectively. Seventeen high risk couples were screened. Among the 17 prenatal diagnosis samples, 2 villus samples contaminated by exogenous DNA were confirmed by MLPA method.

CONCLUSION

MLPA is an effective complement for α-thalassaemia gene deletion detection. The molecular diagnosis strategy and process of gap-PCR combined with MLPA for α- thalassaemia gene deletion detection can prevent the missing of gene deletion, and false-positive or false-negative misdiagnosis of α-thalassaemia in prenatal diagnosis.