Analysis of a mistake occurring during prenatal diagnosis of two couples respectively carrying CD41-42 (-TCTT) and CD43(G>T) mutations of the beta hemoglobin gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To provide prenatal diagnosis for two couples who respectively carried heterozygous CD41-42 (-TCTT) and CD43 (G>T) mutations of the beta hemoglobin gene.</p><p><b>METHODS</b>The mutations were simultaneously detected with reverse dot blot (two diagnostic kits), multi-color melting curve analysis and sequencing analysis.</p><p><b>RESULTS</b>The fetus of family 1 was shown to be heterozygous for CD43 (G>T) by the three methods, while the fetus of family 2 was shown to be double heterozygous for CD41-42 (-TCTT) and CD43 (G>T) by multi-color melting curve analysis and sequencing analysis. The two diagnostic kits yielded different results by reverse dot blot, one as double heterozygous for CD41-42 (-TCTT) and CD43 (G>T), and another as homozygous for CD41-42 (-TCTT).</p><p><b>CONCLUSION</b>For prenatal diagnosis of couples carrying mutations of beta hemoglobin gene such as CD41-42 (-TCTT) and CD43 (G>T), other methods such as Sanger sequencing should be used in order to avoid misdiagnosis.</p>

The application of multicolor probe melting curve analysis for the prenatal diagnosis ofβthalassemia / 中华检验医学杂志

Objective To establish a method of multicolor melting curve analysis for the prenatal diagnosis ofβthalassemia.Methods Methodology establishment.A total of 95 cases, including 9 fetal villi samples(10-13 weeks)and 86 amniotic fluid samples(18-24 weeks)were collected by Center for Prenatal Diagnosis of Shenzhen Maternity and Child Healthcare Hospital between January 2014 and December 2014.A double-blind test was done to detect the mutations of beta globin gene by means of reverse dot ( RDB) blot and multicolor melting curve analysis ( MMCA).The consistency of the two methods is compared.Results The results of 93 cases detected by MMCA and RDB are completely consistent.The results of the 2 cases detected by MMCA after correction are the same as the results detected by RDB.Finally, the coincidence rate of the result was 100%.Conclusion MMCA can be applied to the prenatal diagnosis ofβthalassemia as an effective supplement to RDB.

Application of multiplex ligation-dependent probe amplification technique in prenatal diagnosis of α-thalassemia / 中华医学遗传学杂志

OBJECTIVE To assess the application value of multiplex ligation-dependent probe amplification (MLPA) for the detection of gene deletion and prenatal diagnosis of α-thalassemia. METHODS MLPA was applied for 2 cases with α-thalassemia phenotype by whole blood cell counting and hemoglobin component detection but were ruled out by regular molecular diagnosis. Potential gene deletions and point mutations of α-thalassemia gene were detected with regular Gap-polymerase chain reaction (Gap-PCR) and reverse dot blotting (RDB) in 89 cases where one or both partners were carriers of α-thalassemia mutations. Meanwhile, MLPA was used for detecting α-globin gene deletion among the 89 samples. RESULTS For the 2 cases with α-thalassemia phenotype, no α globin gene deletion was detected by MLPA, but were subsequently confirmed as iron-deficiency anemia. The results of MLPA and Gap-PCR detection for the 88 cases were consistent, except for 1 fetal sample (chorionic villi) which could not be diagnosed by Gap-PCR and was confirmed to be - SEA/αα by MLPA. CONCLUSION MLPA can be applied to prenatal diagnosis of α-thalassemia as an effective supplement to Gap-PCR to reduce both misdiagnosis and missed diagnosis and improve the accuracy of prenatal diagnosis.