A decreased content of sphingolipids was also observed in the hippocampus of FTD patients carrying the risk allele of TMEM106B (Lee et al., 2023), as well as in the frontal cortex white matter of FTD patients carrying the progranulin or C9orf72 repeat expansion mutation (Marian et al., 2023). This evidence concerns the gene GRN and frontotemporal dementia.