Department of Molecular and Clinical Genetics, Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland.
PLoS One. 2012;7(3):e33667. doi: 10.1371/journal.pone.0033667. Epub 2012 Mar 20.
Primary ciliary dyskinesia (PCD) is a rare (1/20,000), multisystem disease with a complex phenotype caused by the impaired motility of cilia/flagella, usually related to ultrastructural defects of these organelles. Mutations in genes encoding radial spoke head (RSPH) proteins, elements of the ciliary ultrastructure, have been recently described. However, the relative involvement of RSPH genes in PCD pathogenesis remained unknown, due to a small number of PCD families examined for mutations in these genes. The purpose of this study was to estimate the involvement of RSPH4A and RSPH9 in PCD pathogenesis among East Europeans (West Slavs), and to shed more light on ultrastructural ciliary defects caused by mutations in these genes. The coding sequences of RSPH4A and RSPH9 were screened in PCD patients from 184 families, using single strand conformational polymorphism analysis and sequencing. Two previously described (Q109X; R490X) and two new RSPH4A mutations (W356X; IVS3_2-5del), in/around exons 1 and 3, were identified; no mutations were found in RSPH9. We estimate that mutations in RSPH4A, but not in RSPH9, are responsible for 2-3% of cases in the East European PCD population (4% in PCD families without situs inversus; 11% in families preselected for microtubular defects). Analysis of the SNP-haplotype background provided insight into the ancestry of repetitively found mutations (Q109X; R490X; IVS3_2-5del), but further studies involving other PCD cohorts are required to elucidate whether these mutations are specific for Slavic people or spread among other European populations. Ultrastructural defects associated with the mutations were analyzed in the transmission electron microscope images; almost half of the ciliary cross-sections examined in patients with RSPH4A mutations had the microtubule transposition phenotype (9+0 and 8+1 pattern). While microtubule transposition was a prevalent ultrastructural defect in cilia from patients with RSPH4A mutations, similar defects were also observed in PCD patients with mutations in other genes.
原发性纤毛运动障碍（PCD）是一种罕见的疾病（1/20,000），具有多种系统表现，其特征为纤毛/鞭毛运动功能障碍，通常与这些细胞器的超微结构缺陷有关。最近已经描述了编码放射辐条头（RSPH）蛋白的基因突变，这些蛋白是纤毛超微结构的组成部分。然而，由于仅对少数 PCD 家系进行了这些基因的突变检测，RSPH 基因突变在 PCD 发病机制中的相对作用仍不清楚。本研究的目的是评估 RSPH4A 和 RSPH9 基因在东欧人（西斯拉夫人）PCD 发病机制中的作用，并进一步阐明这些基因的突变引起的超微结构纤毛缺陷。使用单链构象多态性分析和测序，对来自 184 个家系的 PCD 患者的 RSPH4A 和 RSPH9 的编码序列进行了筛选。在exon 1 和 3 附近发现了两个先前描述的（Q109X；R490X）和两个新的 RSPH4A 突变（W356X；IVS3_2-5del）；RSPH9 未发现突变。我们估计，RSPH4A 基因突变（而非 RSPH9 基因突变）占东欧 PCD 人群病例的 2-3%（无 situs inversus 的 PCD 家系中为 4%；预先选择微管缺陷的家系中为 11%）。SNP-单倍型背景分析为反复出现的突变（Q109X；R490X；IVS3_2-5del）的起源提供了线索，但需要进一步研究其他 PCD 队列，以阐明这些突变是否仅存在于斯拉夫人中，还是在其他欧洲人群中传播。在透射电子显微镜图像中分析了与突变相关的超微结构缺陷；在 RSPH4A 突变患者的纤毛横切面上，近一半观察到微管易位表型（9+0 和 8+1 模式）。虽然微管易位是 RSPH4A 突变患者纤毛的主要超微结构缺陷，但在其他基因突变的 PCD 患者中也观察到类似的缺陷。
