cDNA synthesis
We extracted RNA from blood (human) or brain, liver and kidney (mouse) using Tri Reagent (Thermo Fisher Scientific). The cDNA libraries were prepared using RevertAid First Strand cDNA Synthesis Kit (Thermo Fisher Scientific) primed with a Poly T primer. TMEM251 cDNA was amplified using gene specific primers (Table S3). The cDNA were cloned by T/A cloning into pTZ57R/T vector (Thermo Fisher Scientific) and sequence verified.