Sphingolipid biosynthesis is also required for adipocyte survival, because adipocyte-specific Sptlc1 (another major subunit of SPT) KO mice exhibited a striking age-dependent loss of adipose tissues28 and adipocyte-specific Sptlc2 KO mice exhibited similar lipodystrophy phenotype29. Here, SPTLC1 is linked to lipodystrophy.