Table 2.

Loci associated with type 2 diabetes and fasting glucose

Gene	Name	Function	Traits associated with the gene or risk allele(s) in addition to fasting glucose and type 2 diabetes
ADCY5	Adenylate cyclase 5	Formation of adenylate cyclase
ADRA2A	Adrenergic alpha-2A receptor	This receptor is expressed in β-cells and modulates insulin release	Insulin Secretion
DGKB-TMEM195	Diacylglycerol kinase beta and Transmembrane protein 195	DGKB encodes an isotype of diacylglycerol kinase which increases diacylglycerol and therefore increases insulin secretion. TMEM195 is a membrane phosphoprotein
GCK	Glucokinase	Three tissue-specific forms phosphorylate glucose to produce glucose-6-phosphate in the liver and the β-cell
GCKR	Glucokinase regulator	A regulatory protein that inhibits glucokinase by non-covalent binding to form an inactive complex
MTNR1B	Melatonin receptor 1B	Encodes one of two high affinity forms of a receptor for melatonin	Insulin secretion
PROX1	Prospero protein homeobox 1	This a corepressor of hepatocyte nuclear factor 4α which plays an important role in β-cell development
SLC30A8	Solute carrier family 30 (zinc transporter), member 8	Expressed in β-cells – it is a Zinc transporter, this being necessary for insulin storage in secretory granules (an insulin hexamer with 2 Zn2+) as well as being part of the secretory mechanism	Proinsulin conversion Insulin secretion
TCF7L2	Transcription factor 7-like 2	This gene encodes a high mobility group box-containing transcription factor that plays a key role in the Wnt signaling pathway	Proinsulin conversion Insulin secretion ?Insulin action