Defective primary ciliogenesis or cilium stability forms the basis of human ciliopathies, including Joubert syndrome (JS), with defective cerebellar vermis development. We performed a high-content genome-wide small interfering RNA (siRNA) screen to identify genes regulating ciliogenesis as candidates for JS. We analyzed results with a supervised-learning approach, using SYSCILIA gold standard, Cildb3.0, a centriole siRNA screen and the GTex project, identifying 591 likely candidates. Intersection of this data with whole exome results from 145 individuals with unexplained JS identified six families with predominantly compound heterozygous mutations in KIAA0586. A c.428del base deletion in 0.1% of the general population was found in trans with a second mutation in an additional set of 9 of 163 unexplained JS patients. KIAA0586 is an orthologue of chick Talpid3, required for ciliogenesis and Sonic hedgehog signaling. Our results uncover a relatively high frequency cause for JS and contribute a list of candidates for future gene discoveries in ciliopathies.DOI: http://dx.doi.org/10.7554/eLife.06602.001

Neuronal migration defects, including pachygyria, are among the most severe developmental brain defects in humans. Here, we identify biallelic truncating mutations in CTNNA2, encoding αN-catenin, in patients with a distinct recessive form of pachygyria. CTNNA2 was expressed in human cerebral cortex, and its loss in neurons led to defects in neurite stability and migration. The αN-catenin paralog, αE-catenin, acts as a switch regulating the balance between β-catenin and Arp2/3 actin filament activities. Loss of αN-catenin did not affect β-catenin signaling, but recombinant αN-catenin interacted with purified actin and repressed ARP2/3 actin-branching activity. The actin-binding domain of αN-catenin or ARP2/3 inhibitors rescued the neuronal phenotype associated with CTNNA2 loss, suggesting ARP2/3 de-repression as a potential disease mechanism. Our findings identify CTNNA2 as the first catenin family member with biallelic mutations in humans, causing a new pachygyria syndrome linked to actin regulation, and uncover a key factor involved in ARP2/3 repression in neurons.

Reversible posterior leukoencephalopathy may develop in patients who have renal insufficiency or hypertension or who are immunosuppressed. This syndrome should be recognized immediately and trigger agents can be discontinued to prevent long-term sequelae.

The aim of this study was to determine the clinical characteristics of children demonstrating neurological complications with pandemic influenza (H1N1). We reviewed the medical and laboratory records of all children who were hospitalized with neurological symptoms and who had proven influenza virus infection by reverse transcriptase-polymerase chain reaction on nasal and throat swabs. Eight children aged between 10 months and 7 years had neurological complications due to pandemic influenza (H1N1) and five of them were female. Four of them were previously healthy; there was chronic renal failure (CRF) in one and neurologic disease in three patients. Seven of them had seizure and altered consciousness. Seven of them were followed in pediatric intensive care units. We performed lumbar puncture in four patients and their cerebrospinal fluid examinations showed pleocytosis in one and no cell in three specimens. Neuroimaging was performed in four patients and three of them had abnormalities. We diagnosed aseptic meningitis in one, acute disseminated encephalomyelitis (ADEM) in one, acute necrotizing encephalopathy (ANE) in one, meningoencephalitis in one, and status epilepticus in four patients. All patients were treated with oseltamivir and antiepileptic drugs. One patient with CRF died; four previously healthy patients recovered fully, and three patients who had neurologic disorder returned to their previous neurological status. In conclusion, during pandemic influenza (H1N1) infection, neurological complications may be seen in addition to the respiratory infection. The type of neurological involvement may be variable such as triggering seizure, aseptic meningitis, encephalitis, ADEM, and ANE. Neurological complications frequently recover fully especially in previously healthy children, but sometimes a severe clinical course occurs.

Cardiac abnormalities have potential long-term hemodynamic consequences that justify an early diagnosis. Thus, for any patient with NF1, a cardiologic assessment is mandatory at the time of diagnosis and with regular follow-up intervals.