Center for Medical Genetics, Ghent University, Belgium.
J Hum Genet. 2010 Feb;55(2):112-7. doi: 10.1038/jhg.2009.132. Epub 2010 Jan 15.
Mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), a heritable disease that affects elastic fibers. Thus far, >200 mutations have been characterized by various PCR-based techniques (primarily direct sequencing), identifying up to 90% of PXE-causing alleles. This study wanted to assess the importance of deletions and insertions in the ABCC6 genomic region, which is known to have a high recombinational potential. To detect ABCC6 deletions/insertions, which can be missed by direct sequencing, multiplex ligation-dependent probe amplification (MLPA) was applied in PXE patients with an incomplete genotype. MLPA was performed in 35 PXE patients with at least one unidentified mutant allele after exonic sequencing and exclusion of the recurrent exon 23-29 deletion. Six multi-exon deletions and four single-exon deletions were detected. Using MLPA in addition to sequencing, we expanded the ABCC6 mutation spectrum with 9 novel deletions and characterized 25% of unidentified disease alleles. Our results further illustrate the instability of the ABCC6 genomic region and stress the importance of screening for deletions in the molecular diagnosis of PXE.
ABCC6 基因突变导致弹性假黄瘤（PXE），这是一种遗传性疾病，影响弹性纤维。到目前为止，已经通过各种基于 PCR 的技术（主要是直接测序）鉴定了 >200 种突变，鉴定了多达 90%的 PXE 致病等位基因。本研究旨在评估 ABCC6 基因组区域缺失和插入的重要性，该区域已知具有高重组潜能。为了检测直接测序可能遗漏的 ABCC6 缺失/插入，在有不完全基因型的 PXE 患者中应用了多重连接依赖性探针扩增（MLPA）。在经过外显子测序排除了反复出现的外显子 23-29 缺失后，对 35 名至少有一个未识别突变等位基因的 PXE 患者进行了 MLPA。检测到 6 个多外显子缺失和 4 个单外显子缺失。通过在测序的基础上使用 MLPA，我们扩展了 ABCC6 突变谱，发现了 9 个新的缺失，并对 25%的未识别疾病等位基因进行了特征描述。我们的结果进一步说明了 ABCC6 基因组区域的不稳定性，并强调了在 PXE 的分子诊断中筛查缺失的重要性。
