{Reference Type}: Case Reports {Title}: Identification of a pathogenic deep intronic variant in ATRX ends a diagnostic odyssey. {Author}: van der Smagt JJ;Lampri AP;de Lange I;Alders M;Houben ML;Koudijs MJ;van Jaarsveld RH; {Journal}: Eur J Med Genet {Volume}: 69 {Issue}: 0 {Year}: 2024 Jun 24 {Factor}: 2.465 {DOI}: 10.1016/j.ejmg.2024.104949 {Abstract}: Variation in the non-coding genome is being increasingly recognized to be involved in monogenic disease etiology. However, the interpretation of non-coding variation is complicated by a lack of understanding of how non-coding genetic elements function. Additional lines of evidence are therefore needed to recognize non-coding variants as pathogenic. We here present a case where a collective body of evidence resulted in the identification and conclusive classification of a pathogenic deep intronic variant in ATRX. This report demonstrates the utility of a multi-platform approach in aiding the identification of pathogenic variants outside coding regions. Furthermore, it marks the first reported instance of a deep intronic pathogenic variant in ATRX.