CFAP300: Mutations in Slavic Patients with Primary Ciliary Dyskinesia and a Role in Ciliary Dynein Arms Trafficking.

Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous hereditary disease from a class of ciliopathies. In spite of the recent progress, the genetic basis of PCD in one-third of patients remains unknown. In search for new genes and/or mutations, whole-exome sequencing was performed in 120 unrelated Polish patients with PCD, in whom no genetic cause of PCD was earlier identified. Among a number of pathogenic variants in PCD genes, mutations in CFAP300 (alias C11orf70) were detected. Extended screening in the whole Polish PCD cohort revealed the relatively high frequency (3.6%) of otherwise rare c.[198_200 del_insCC] variant, indicating that it should be included in population-specific genetic tests for PCD in Slavic populations. Immunofluorescence analysis of the respiratory epithelial cells from patients with CFAP300 mutations revealed the absence or aberrant localization of outer and inner dynein arm markers, consistent with transmission electron microscope images indicating the lack of both dynein arms. Interestingly, the disparate localization of DNAH5 and DNALI1 proteins in patients with CFAP300 mutations suggested differential mechanisms for the trafficking of preassembled outer and inner dynein arms to the axoneme. The profile of CFAP300 expression during ciliogenesis in suspension culture was consistent with its role in cilia assembly. Gene silencing experiments, performed in a model organism, Schmidtea mediterranea (flatworm), pointed to the conserved role of CFAP300 in ciliary function.

Primary ciliary dyskinesia among Arabs: Where do we go from here?

Primary ciliary dyskinesia (PCD), also known as immotile-cilia syndrome, is a rare genetic disease that is inherited in an autosomal recessive manner. Several studies have explored certain aspects of PCD in the Arab world, yet much is still lacking in terms of identifying the different characteristics of this disease. In this paper, we aim to briefly cover those studies published about PCD in Arab countries, as well as to provide recommendations and guidelines for future studies.

Syndromic ciliopathies: From single gene to multi gene analysis by SNP arrays and next generation sequencing.

Joubert syndrome (JS) and related disorders (JSRD), Meckel syndrome (MKS) and Bardet-Biedl syndrome (BBS) are autosomal recessive ciliopathies with a broad clinical and genetic overlap. In our multiethnic cohort of 88 MKS, 61 JS/JSRD and 66 BBS families we performed genetic analyses and were able to determine mutation frequencies and detection rates for the most frequently mutated MKS genes. On the basis of determined mutation frequencies, a next generation gene panel for JS/JSRD and MKS was established. Furthermore 35 patients from 26 unrelated consanguineous families were investigated by SNP array-based homozygosity mapping and subsequent DNA sequencing of known candidate genes according to runs of homozygosity size in descending order. This led to the identification of the causative homozygous mutation in 62% of unrelated index cases. Based on our data we discuss various strategies for diagnostic mutation detection in the syndromic ciliopathies JS/JSRD, MKS and BBS.

Nine Japanese patients with immotile-dyskinetic cilia syndrome: an ultrastructural study using tannic acid-containing fixation.

Respiratory cilia and sperm flagella of nine Japanese patients with immotile-dyskinetic cilia syndrome were studied ultrastructurally by using a tannic acid-containing fixative. Respiratory cilia from two female patients with Kartagener's syndrome and one male patient with situs inversus and sinobronchitis were completely immotile and lacked both dynein arms. However, approximately 30% of the spermatozoa from the male patient were weakly motile. In four patients with immotile cilia syndrome without Kartagener's triad, immotile respiratory cilia generally lacked the inner dynein arms. Two clinically unusual cases, an 11-year-old boy and a 29-year-old woman with prolonged saccharin test, recurrent bronchitis, and bronchiectasia, possessed motile respiratory cilia. Ultrastructurally, both dynein arms were normal, but numerous defective central pairs (more than 50% and 70%, respectively) were seen, and the defect in the second case was similar to the transposition of microtubules reported by Sturgess et al (N Engl J Med 303:318-322, 1980). However, defects in the first case were unique and may be congenital. We propose a new type of dyskinetic cilia syndrome with defective central pairs. Additionally, nasal cilia from a 35-year-old man with immotile cilia syndrome contained excess large singlets within ciliary axonemes consisting of 17 protofilaments.