Cellular ciliary phenotyping indicates pathogenicity of novel variants in IFT140 and confirms a Mainzer–Saldino syndrome diagnosis

• DOI: 10.1186/s13630-018-0055-2
• Publication Date: 2018-02-23T11:16:05Z
• Authors: Machteld M. Oud; Brooke L. Latour; Zeineb Bakey; Stef J. Letteboer; Dorien Lugtenberg; Ka Man Wu; Elisabeth A. M. C...; Helger G. Yntema; Miriam Schmidts; Ronald Roepman; Ernie M. H. F. Bo...
• Keywords: Ciliopathy; Intraflagellar Transport; Ciliogenesis; Bardet–Biedl Syndrome; Ciliopathies; Haploinsufficiency

Mainzer–Saldino syndrome (MZSDS) is a skeletal ciliopathy and part of the short-rib thoracic dysplasia (SRTD) group ciliary disorders. The main characteristics MZSDS are short limbs, mild narrow thorax, blindness, renal failure. Thus far, variants in two genes associated with MZSDS: IFT140, IFT172. In this study, we describe 1-year-old girl presenting abnormalities, Leber congenital amaurosis, bilateral hearing difficulties. For establishing an accurate diagnosis, combined clinical, molecular, functional analyses. We performed diagnostic whole-exome sequencing (WES) analysis to determine genetic cause disease analyzed gene panels, containing all currently known vision disorders, impairment. Upon detection likely causative variants, phenotyping was patient urine-derived epithelial cells (URECs) rescue experiments were CRISPR/Cas9-derived Ift140 knock out pathogenicity detected vitro. Cilium morphology, cilium length, intraflagellar transport (IFT) evaluated by immunocytochemistry. Diagnostic WES revealed novel compound heterozygous encoding IFT140. Thorough investigation data did not reveal any candidate Patient-derived URECs accumulation IFT-B protein IFT88 at tip 41% indicative impaired retrograde IFT, while absent cilia from control URECs. Furthermore, transfection IFT140 construct mutation p.Tyr923Asp resulted significantly higher percentage than wild-type construct. By combining genetic, could conclude that has SRTD9, also called syndrome, caused suggest possibility may underlie Moreover, show urine provides excellent source obtain patient-derived non-invasive manner study testing.