MRM2 and Menkes disease: Whereas a polymorphism in METTL15 is associated with obesity [114] and a polymorphism in TFB1M is associated with type 2 diabetes [115], only a single primary MD is associated with mutations in the MRM2 gene involved in mt-rRNA modification: mitochondrial DNA depletion syndrome 17 (OMIM #618567) with infancy onset [116].