Between 2006 and 2017, the median CD4 count increased from 190 cells/μl to 331 cells/μl (p<0.0001), and the proportions of patients with LI and AHD decreased from 76% to 47% (p< 0.0001) and from 18.7% to 8.9% (p<0.0001), respectively. This evidence concerns the gene CD4 and mitochondrial DNA depletion syndrome 4a.