Molecular evaluation of foetuses with holoprosencephaly shows high incidence of microdeletions in the HPE genes
Molecular evaluation of foetuses with holoprosencephaly shows high incidence of microdeletions in the HPE genes
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DOI：
10.1007/s00439-005-0097-6
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发表时间：
2006-03-01
期刊：
影响因子：
5.3
通讯作者：
David, V
中科院分区：
文献类型：
--
作者：
Bendavid, C;Dubourg, C;David, V
前脑无裂畸形 (HPE) 是人类最常见的前脑结构畸形，可以在怀孕早期通过产前超声检查进行检测。在核型正常的胎儿中，14% 的四个主要 HPE 基因（SHH、ZIC2、SIX3 和 TGIF）存在突变。基因组重排现已与许多遗传疾病有关，因此我们假设主要 HPE 基因的微缺失在具有严重表型或其他相关畸形的 HPE 胎儿中也可能很常见。我们筛选了从 94 个具有正常核型的 HPE 胎儿获得的 DNA，以确定是否存在涉及四个主要 HPE 基因（SHH、ZIC2、SIX3 和 TGIF）的微缺失。其中 13 个胎儿的 4 个基因之一存在点突变，81 个胎儿没有已知的突变。使用短荧光片段定量多重 PCR (QMPSF) 分析快速测定 HPE 基因拷贝数，并通过实时定量 PCR 或荧光原位杂交 (FISH)（如果有细胞系）确认已识别的微缺失。 94个胎儿中有8个（8.5%）检测到微缺失（SHH基因2个，SIX3基因2个，ZIC2基因3个，TGIF基因1个），并且仅在核型正常且无点突变的81个胎儿中检测到微缺失。这些数据表明，四个主要 HPE 基因的微缺失以及点突变是产前 HPE 的常见原因，并且使正常核型胎儿的总诊断率接近 22.3%。检测可以通过 QMPSF 测试方法来实现，该方法被证明可以有效地在一次测定中测试多个基因。
Holoprosencephaly (HPE), the most common structural malformation of the forebrain in humans, can be detected early during pregnancy using prenatal ultrasonography . Among foetuses with a normal karyotype, 14% have mutations in the four main HPE genes (SHH, ZIC2, SIX3 and TGIF). Genomic rearrangements have now been implicated in many genetic diseases, so we hypothesized that microdeletions in the major HPE genes may also be common in HPE foetuses with severe phenotype or other associated malformations. We screened the DNA obtained from 94 HPE foetuses with a normal karyotype for the presence of microdeletions involving the four major HPE genes (SHH, ZIC2, SIX3 and TGIF). Thirteen of the foetuses had a point mutation in one of the 4 genes and 81 had no known mutations. Quantitative multiplex PCR of short fluorescent fragments (QMPSF) analysis was used for rapid determination of HPE genes copy numbers and the identified microdeletions were confirmed by real time quantitative PCR, or fluorescent in situ hybridization (FISH) (if a cell line was available). Microdeletions were detected in 8 of 94 foetuses (8.5%) (2 in SHH, 2 in SIX3, 3 in ZIC2 and 1 in TGIF genes), and only among the 81 foetuses with a normal karyotype and no point mutations. These data suggest that microdeletions in the four main HPE genes are a common cause of prenatal HPE, as well as point mutations, and increase the total diagnosis rate close to approximate to 22.3% of foetuses with normal karyotype. Detection can be achieved by the QMPSF testing method that proved to be efficient for testing several genes in a single assay.