SQSTM1/p62 variants in 486 patients with familial ALS from Germany and Sweden.
Neurobiol Aging. 2019 Nov 2. pii: S0197-4580(19)30382-3. doi: 10.1016/j.neurobiolaging.2019.10.018. [Epub ahead of print]
|Authors/Editors:||Yilmaz R, Müller K, Brenner D, Volk AE, Borck G, Hermann A, Meitinger T, Strom TM, Danzer KM, Ludolph AC, Andersen PM, Weishaupt JH; German ALS Network MND-NET.|
Several studies reported amyotrophic lateral sclerosis (ALS)-linked mutations in TBK1, OPTN, VCP, UBQLN2, and SQSTM1 genes encoding proteins involved in autophagy. SQSTM1 was originally identified by a candidate gene approach because it encodes p62, a multifunctional protein involved in protein degradation both through proteasomal regulation and autophagy. Both p62 and optineurin (encoded by OPTN) are direct interaction partners and substrates of TBK1, and these 3 proteins form the core of a genetic and functional network that may connect autophagy with ALS. Considering the molecular and conceptual relevance of the TBK1/OPTN/SQSTM1 “triangle,” we here performed a targeted screen for SQSTM1 variants in 486 patients with familial ALS from Germany and Sweden by analyzing whole-exome sequencing data. We report 9 novel and 5 previously reported rare variants in SQSTM1 and discuss the current evidence for SQSTM1 as a primary disease gene for ALS. We conclude that the evidence for causality remains vague for SQSTM1 and is weaker than for the other autophagy genes, for example, TBK1 and OPTN.