Application of DNA Microarray in Genetic Mutation Detection in Patients with Thalassemia / 中国实验血液学杂志

OBJECTIVE@#To perform dried blood spots thalassemia gene detection in patients with positive blood phenotypes by microarray technology, and evaluate its value in clinical detection.@*METHODS@#DNA samples were extracted from dried blood spots of 410 patients. Microarray technology was used to detect 3 deletion and 3 non-deletion types of α-thalassemia and 19 β-thalassemia point mutations which were common gene mutions in China.@*RESULTS@#There were 357 positive cases in all the 410 tested samples with the positive rate 87.07%, among which 299 cases (72.93%) carried deletion or point mutations of α-thalassemia, 29 cases (7.07%) carried point mutations of β-thalassemia and 29 cases (7.07%) carried gene mutations of complex αβ-thalassemia syndrome. The mutations of α-thalassemia were involved with --@*CONCLUSION@#The most common genetic mutations are --

Methodological Evaluation of Microarray in the Detection of α-Thalassemia / 中国实验血液学杂志

OBJECTIVE@#To proceed the clinical evaluation of DNA microarray for thalassemia gene detection.@*METHODS@#Peripheral blood samples of 166 thalassemia gene test subjects were collected and tested for thalassemia genes by microarray chip method and Gap-PCR method combined with PCR-reverse dot blot hybridization method according to double-blind control test. The specificity, sensitivity, positive predictive value, negative predictive value, and total coincidence rate of the microarray chip method were evaluated. When the two methods were inconsistent, multiplex ligation dependent probe amplification (MLPA) was used to verify the deletional α-thalassemia.@*RESULTS@#Compared with Gap-PCR method, specificity, sensitivity, positive predictive value, negative predictive value, Youden index, and total coincidence rate of microarray chip method was 100% (70/70), 96.88% (93/96), 100% (93/93), 95.89% (70/73), 0.969, and 97.59% (162/166), respectively, while compared with PCR-reverse dot blot hybridization method was 100% (125/125), 100% (41/41), 100% (41/41), 100% (125/125), 1, and 100% (166/166), respectively.@*CONCLUSION@#The microarray chip method for α-thalassemia gene detection shows the advantages of high specificity, sensitivity, and throughput.

Identification of gene mutation and prenatal diagnosis in a family with X-linked ichthyosis / 中国当代儿科杂志

X-linked ichthyosis (XLI) is a metabolic disease with steroid sulfatase deficiency and often occurs at birth or shortly after birth. The encoding gene of steroid sulfatase, STS, is located on the short arm of the X chromosome, and STS deletion or mutation can lead to the development of this disease. This study collected the data on the clinical phenotype from a family, and the proband, a boy aged 11 years with full-term vaginal delivery, had dry and rough skin and black-brown scaly patches, mainly in the abdomen and extensor aspect of extremities. Peripheral blood samples were collected from each family member and DNA was extracted. Multiplex ligation-dependent probe amplification (MLPA) was used to measure the copy number of STS on the X chromosome. Whole-genome microarray was used to determine the size of the segment with microdeletion in the X chromosome. MLPA was then used for prenatal diagnosis for the mother of the proband. The results revealed that the proband and another two male patients had hemizygotes in STS deletion. Gene microarray identified a rare deletion with a size of 1.6 Mb at Xp22.31 (chrX: 6,516,735-8,131,442). Two female family members were found to be carriers. Prenatal diagnosis showed that the fetus carried by the proband's mother was a carrier of this microdeletion. This study showed STS gene deletion in this family of XLI, which causes the unique skin lesions of XLI. MLPA is a convenient and reliable technique for the molecular and prenatal diagnosis of XLI.

Application of multiplex ligation-dependent probe amplification to diagnosis and prenatal diagnosis of common aneuploidies / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the application value of the multiplex ligation-dependent probe amplification (MLPA) technique in diagnosis and prenatal diagnosis of chromosomes 13, 18, 21, X and Y aneuploidy.</p><p><b>METHODS</b>Forty-four cases including 30 peripheral blood samples, 10 fetal cord blood samples, and 4 amniotic fluid samples were collected in this study. DNA was isolated from the samples and detected by MLPA, followed by analyzing in ABI310 Genetic Analyzer. Analysis of copy number changes for chromosomes 13, 18, 21, X and Y was carried out with RH-MLPA-analysis software. The routine karyotype analyses were also done for all the samples.</p><p><b>RESULTS</b>Of 44 samples, the results of 42 by MLPA method was consistent with that by chromosome karyotyping. Only one case with trisomy 21 chimerism was failed to reach conclusion. In addition, one case of mark chromosome segment was identified as Y-chromosome segment by MLPA, while karyotyping failed to make judgment. The accurate rate of MLPA was 97.7% (43/44).</p><p><b>CONCLUSION</b>The MLPA technique can simultaneously detect dozens of different target sequences and their copy number changes in a single reaction. It showed high specificity, good reproducibility, was fast and high-throughput. The MLPA technique can be applied to diagnosis and prenatal diagnosis of the common chromosomal aneuploidy.</p>