TY - JOUR T1 - <em>IFT81</em>, encoding an IFT-B core protein, as a very rare cause of a ciliopathy phenotype JF - Journal of Medical Genetics JO - J Med Genet SP - 657 LP - 665 DO - 10.1136/jmedgenet-2014-102838 VL - 52 IS - 10 AU - Isabelle Perrault AU - Jan Halbritter AU - Jonathan D Porath AU - Xavier Gérard AU - Daniela A Braun AU - Heon Yung Gee AU - Hanan M Fathy AU - Sophie Saunier AU - Valérie Cormier-Daire AU - Sophie Thomas AU - Tania Attié-Bitach AU - Nathalie Boddaert AU - Michael Taschner AU - Markus Schueler AU - Esben Lorentzen AU - Richard P Lifton AU - Jennifer A Lawson AU - Meriem Garfa-Traore AU - Edgar A Otto AU - Philippe Bastin AU - Catherine Caillaud AU - Josseline Kaplan AU - Jean-Michel Rozet AU - Friedhelm Hildebrandt Y1 - 2015/10/01 UR - http://jmg.bmj.com/content/52/10/657.abstract N2 - Background Bidirectional intraflagellar transport (IFT) consists of two major protein complexes, IFT-A and IFT-B. In contrast to the IFT-B complex, all components of IFT-A have recently been linked to human ciliopathies when defective. We therefore hypothesised that mutations in additional IFT-B encoding genes can be found in patients with multisystemic ciliopathies.Methods We screened 1628 individuals with reno-ocular ciliopathies by targeted next-generation sequencing of ciliary candidate genes, including all IFT-B encoding genes.Results Consequently, we identified a homozygous mutation in IFT81 affecting an obligatory donor splice site in an individual with nephronophthisis and polydactyly. Further, we detected a loss-of-stop mutation with extension of the deduced protein by 10 amino acids in an individual with neuronal ceroid lipofuscinosis-1. This proband presented with retinal dystrophy and brain lesions including cerebellar atrophy, a phenotype to which the IFT81 variant might contribute. Cultured fibroblasts of this latter affected individual showed a significant decrease in ciliated cell abundance compared with controls and increased expression of the transcription factor GLI2 suggesting deranged sonic hedgehog signalling.Conclusions This work describes identification of mutations of IFT81 in individuals with symptoms consistent with the clinical spectrum of ciliopathies. It might represent the rare case of a core IFT-B complex protein found associated with human disease. Our data further suggest that defects in the IFT-B core are an exceedingly rare finding, probably due to its indispensable role for ciliary assembly in development. ER -