Genetics and Prenatal Diagnosis Center, The Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China.
Hunan Research Center for Big Data Application in Genomics Genetalks Inc., Changsha, 410152, Hunan, China.
BMC Med Genomics. 2021 Nov 22;14(1):275. doi: 10.1186/s12920-021-01128-1.
Relative haplotype dosage (RHDO) approach has been applied in noninvasive prenatal diagnosis (NIPD) of Duchenne muscular dystrophy (DMD). However, the RHDO procedure is relatively complicated and the parental haplotypes need to be constructed. Furthermore, it is not suitable for the diagnosis of de novo mutations or mosaicism in germ cells. Here, we investigated NIPD of DMD using a relative mutation dosage (RMD)-based approach-cell-free DNA Barcode-Enabled Single-Molecule Test (cfBEST), which has not previously been applied in the diagnosis of exon deletion.
Five DMD families caused by DMD gene point mutations or exon deletion were recruited for this study. After the breakpoints of exon deletion were precisely mapped with multiple PCR, the genotypes of the fetuses from the five DMD families were inferred using cfBEST, and were further validated by invasive prenatal diagnosis.
The cfBEST results of the five families indicated that one fetus was female and did not carry the familial molecular alteration, three fetuses were carriers and one was male without the familial mutation. The invasive prenatal diagnosis results were consistent with those of the cfBEST procedure.
This is the first report of NIPD of DMD using the RMD-based approach. We extended the application of cfBEST from point mutation to exon deletion mutation. The results showed that cfBEST would be suitable for NIPD of DMD caused by different kinds of mutation types.
相对单体型剂量（RHDO）方法已应用于杜氏肌营养不良症（DMD）的无创性产前诊断（NIPD）。然而，RHDO 程序相对复杂，需要构建父母单体型。此外，它不适合用于诊断生殖细胞中的新生突变或嵌合体。在这里，我们使用基于相对突变剂量（RMD）的方法-无细胞游离 DNA 条码单分子检测（cfBEST）研究了 DMD 的 NIPD，该方法以前未应用于exon 缺失的诊断。
招募了五个由 DMD 基因突变或 exon 缺失引起的 DMD 家系进行本研究。在用多重 PCR 精确映射 exon 缺失的断点后，使用 cfBEST 推断五个 DMD 家系的胎儿基因型，并通过侵入性产前诊断进行进一步验证。
五个家系的 cfBEST 结果表明，一个胎儿为女性，不携带家族性分子改变，三个胎儿为携带者，一个为男性，没有家族性突变。侵入性产前诊断结果与 cfBEST 程序的结果一致。
这是首次使用基于 RMD 的方法进行 DMD 的 NIPD 报告。我们将 cfBEST 的应用从点突变扩展到 exon 缺失突变。结果表明，cfBEST 将适用于不同突变类型引起的 DMD 的 NIPD。
