SNORD54: SNORD54 is a small nucleolar RNA (snoRNA) that has been found to be differentially expressed in various conditions, including post-traumatic stress disorder (PTSD) [PMC7830144, PMC6533054]. It is downregulated in lymphocytes of individuals with PTSD after the 9/11 attacks [PMC6533054]. Additionally, SNORD54 has been implicated in autism spectrum disorder and immune system function [PMC5802695]. It is one of the genes that are differentially expressed in WTC responders with PTSD [PMC7830144]. SNORD54 is part of the H/ACA group of snoRNAs and has shown upregulation in microarray analyses [PMC3241684]. However, its expression levels were found to be lower when measured by qPCR [PMC5363543]. SNORD54 has also been identified as one of the genes that remain significant when considering exonic counts [PMC5802695]. Furthermore, it has been used as an internal control to normalize gene expression in certain studies [PMC5386523]. Dysregulation of SNORD54 has been suggested as a potential biomarker in chronic lymphocytic leukemia and colorectal carcinogenesis [PMC8518074]. In summary, SNORD54 is a snoRNA that shows differential expression in various conditions and plays a role in PTSD, autism spectrum disorder, immune system function, chronic lymphocytic leukemia, and colorectal carcinogenesis. It has been identified as one of the genes differentially expressed in WTC responders with PTSD. However, its expression levels can vary depending on the method used for measurement.