NOD2 and Yao syndrome: Interestingly, a new concept in genomic medicine termed genetically transitional disease (GTD) seems to better define Yao syndrome (YAOS) (4), a NOD2-associated AID (NAID), linked to the nucleotide-binding oligomerization domain containing 2 (NOD2) gene, encoding a cytosolic NOD-like receptor (NLR) and innate immune sensor (Online Mendelian Inheritance in Man [OMIM] 617321) (5).