SMAD9 and amyotrophic lateral sclerosis: We found that several mRNAs previously associated with ALS were significantly elevated (adjusted p-value < 0.05), including collagen type XIX, alpha 1 (COL19A1) mRNA, previously associated with higher mortality and fast progression [45], and SMAD9 (also known as SMAD8) mRNA, encoding a muscle biomarker that is broadly increased in ALS muscle and tracks disease progression [18].