A pathologic expansion of a noncoding GGGGCC hexanucleotide repeat of the C9orf72 gene has been strongly associated with familial amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD) cases predominantly in Caucasian populations. In the last decade, scientific interest had been drawn to this gene and many studies conducted have shown a possible correlation with other neurodegenerative diseases as well. We performed an extensive literature search for C9orf72 mutation and its frequency in various neurological and psychiatric diseases. In addition, we performed a meta-analysis of the data related to ALS and familial ALS. An online cloud-based database and an interactive map were developed. The overall mutation frequency of C9orf72 is 20% for familial FTD, 16% for familial ALS and around 6%-8% for sporadic ALS and FTD. The updated meta-analysis that we performed showed that the pooled frequency of C9orf72 repeat expansion in patients with familial ALS was 23% (CI: 18%-28%) and in patients with sporadic ALS 3% (CI: 3%-4%). The subgroup analysis regarding the origin of the population revealed significant differences between Caucasian and Asian patients. Our analysis supports the direct causal relation of the C9orf72 expansion in ALS and FTD. On the contrary, the role of C9orf72 in other neurodegenerative disorders remains controversial. The system that we developed-the online database and the interactive map-is hopefully a stepping stone for an ever-growing platform that will aid scientists from all over the world in contributing to the meta-analysis of C9orf72-related publications.

Background. Due to inadequate UV exposure, intake of small quantities of vitamin D is recommended to prevent musculoskeletal disease. Both basic science and observational literature strongly suggest that higher doses may benefit specific populations and have non-musculoskeletal roles. Evaluating the evidence surrounding high dose supplementation can be challenging given a relatively large and growing body of clinical trial evidence spanning time, geography, populations and dosing regimens. Study objectives were to identify and summarize the clinical trial literature, recognize areas with high quality evidence, and develop a resource database that makes the literature more immediately accessible to end users. Methods. Medline (1946 to January 2015), Embase (1974 to January 2015), and Cochrane databases (January 2015), were searched for trials. All pediatric (0-18 years) trials administering doses higher than 400 IU (<1 year) or 600 IU (≥1 year) were included. Data was extracted independently by two of the authors. An online searchable database of trials was developed containing relevant extracted information (http://www.cheori.org/en/pedvitaminddatabaseOverview). Sensitivity and utility were assessed by comparing the trials in the database with those from systematic reviews of vitamin D supplementation including children. Results. A total of 2,579 candidate papers were identified, yielding 169 trials having one or more arms meeting eligibility criteria. The publication rate has increased significantly from 1 per year (1970-1979) to 14 per year (2010-2015). Although 84% of the total trials focused on healthy children or known high risk populations (e.g., renal, prematurity), this proportion has declined in recent years due to the rise in trials evaluating populations and outcomes not directly related to the musculoskeletal actions of vitamin D (27% in 2010s). Beyond healthy children, the only pediatric populations with more than 50 participants from low risk of bias trials evaluating a clinically relevant outcome were prematurity and respiratory illness. Finally, we created and validated the online searchable database using 13 recent systematic reviews. Of the 38 high dose trials identified by the systematic review, 36 (94.7%) could be found within the database. When compared with the search strategy reported in each systematic review, use of the database reduced the number of full papers to assess for eligibility by 85.2% (±13.4%). Conclusion. The pediatric vitamin D field is highly active, with a significant increase in trials evaluating non-classical diseases and outcomes. Despite the large overall number there are few high quality trials of sufficient size to provide answers on clinical efficacy of high-dose vitamin D. An open access online searchable data should assist end users in the rapid and comprehensive identification and evaluation of trials relevant to their population or question of interest.