When genes are expressed, RNA transcripts are formed. In the case of protein-coding genes called exons, mRNA transcripts are transcribed. Studying the expression of all genes, and all the RNA transcripts that come from such genes, is known as transcriptomics. Transcriptomic approaches of studying genetic diseases enable researchers to better understand how certain genes are expressed in a tissue sample or a single cell.
NKX2-5 - Dilated cardiomyopathy: left ventricle. Homo sapiens.