Ultra-Early Diffuse Lung Disease in an Infant with Pathogenic Variant in Telomerase Reverse Transcriptase (TERT) Gene.

The pathogenic variants in the telomerase reverse transcriptase (TERT) gene have been identified in adults with idiopathic pulmonary fibrosis, while their connection to childhood diffuse lung disease has not yet been described. Within this study, we present a case of a five-month-old, previously healthy infant, with early-onset respiratory failure. The clinical suspicion of diffuse lung disease triggered by cytomegalovirus (CMV) pneumonitis was based on clinical and radiological presentation. Multiorgan involvement was not confirmed. Considering the possible connection between CMV pneumonitis and early-onset respiratory failure, clinical exome sequencing was performed and a novel variant, classified as likely pathogenic in the TERT gene (c.280A>T, p.Lys94Ter) was detected. After segregation analysis yielded negative results, the de novo status of the variant was confirmed. Respiratory support, antiviral and anti-inflammatory therapy offered modest benefits, nevertheless, eighteen months after the initial presentation of disease, an unfavourable outcome occurred. In conclusion, severe viral pneumonia has the potential to induce extremely rare early-onset diffuse lung disease accompanied by chronic respiratory insufficiency. This is linked to pathogenic variants in the TERT gene. Our comprehensive presentation of the patient contributes to valuable insights into the intricate interplay of genetic factors, clinical presentations, and therapeutic outcomes in cases of early-onset respiratory failure.