Adolescent idiopathic scoliosis (AIS) is a genetically heterogeneous disease characterised by three-dimensional deformity of the spine in the absence of a congenital spinal anomaly or neurological musculoskeletal disorder. The clinical variability and incomplete penetrance of some genes linked with AIS indicate that this disease constitutes an oligogenic trait.
We aimed to explore the oligogenic nature of this disease and identify novel AIS genes.
We analysed rare damaging variants within AIS-associated genes by using exome sequencing in 40 AIS trios and 183 sporadic patients.
Multiple variants within AIS-associated genes were identified in eight AIS trios, and five individuals harboured rare damaging variants in the FLNB gene. The patients showed more frequent oligogenicity than the controls. In the gene-based burden test, the top signal resided in FLNB. In functional studies, we found that the AIS-associated FLNB variants altered the protein\'s conformation and subcellular localisation and its interaction with other proteins (TTC26 and OFD1) involved in AIS. The most compelling evidence of an oligogenic basis was that the number of rare damaging variants was recognised as an independent prognostic factor for curve progression in Cox regression analysis.
Our data indicate that AIS is an oligogenic disease and identify FLNB as a susceptibility gene for AIS.

We investigated all coding regions of 17 known amyotrophic lateral sclerosis (ALS)-related genes in 311 sporadic ALS patients who were of Chinese ancestry using next-generation sequencing technology. All nonsynonymous variants identified were confirmed by Sanger sequencing. 29 (9.32%) patients harbored at least one pathogenic or likely pathogenic variants. Nine (2.8%) patients harbored two or three variants which frequency <1% in population databases that may be related to oligogenic pathogenesis. A higher allele frequency was observed in East Asian than in European patients for the majority variants identified in this screening, which may indicate that genetic factors are responsible for the different clinical characteristics between Chinese and European ALS patients. Our study reports the results of extensive genetic screening and is the first to investigate the possible oligogenic pathogenesis in Chinese sporadic ALS patients. These findings are useful for exploring ALS pathogenesis and treatment strategies.