Table 2. Candidate genes for allergic diseases and their function.

Chromosome	Candidate gene	Function
1p31.2	IL-12 receptors β2 chain	Signal transducer of IL-12
2q33	CD28	Co-stimulator in T-cell activation
	CTLA-4	Co-stimulator in T-cell activation
3p24.2–p22	CC chemokine receptor	Signal transducer of chemokine
3q27	BCL6	Repression of Stat6-activated transcription
5q31	IL-4	Differentiation of Th2 cells/induction of IgE production
	IL-5	Eosinophils growth and activation/Promotion of IgE production
	IL-9	Mast cell growth factor
	IL-13	Induction of IgE production
5q31–33	IL-12 p40	Inhibition of Th2 activity
5q33	T-cell membrane proteins (TIMs)	Induction of IL-4 and IL-13 production
5q35	Leukotriene C4 synthase	Synthesis of leukotriene
6p21	Major histocompatibility complex (HLA)	Presentation of antigenic peptide
	Tumour necrosis factors	Induction of inflammation
	Transports involved in antigen processingand and presentation (TAP-1 and TAP-2)	Transportation of antigenic peptide
7p15	IL-6	Promotion of IgE production
	T-cell receptor γ chain	Recognition of antigen
7q35	T-cell receptor β chain	Recognition of antigen
9q34	Complement factor 5	Induction of IL-12 production
10p14	GATA3	Transcription factor in Th2 differentiation
11q13	FcεRI β subunit	Amplifier of IgE signalling
12q13–14	STAT6	Transcription factor in IL-4 signalling
12q14	Stem cell factor	Mast cell growth factor
12q21	IFN-γ	Inhibition of Th2 activity/Inhibition of IgE isotype classwitch
12q22	Leukotriene A4 hydrolase	Synthesis of leukotriene
14q11.2–q13	T-cell receptor α/δ chain	Recognition of antigen
16p12	IL-4 receptor α chain	Signal transducer of IL-4
17p11	CC chemokine	Recruitment and activation of inflammatory cells
19q13.3	Complement factor 5a receptor	Induction of IL-12 production
Xq13	IL-13 receptor α1/α2 chain	Signal transducer of IL-13

IL-12, interleukin-12; IFN-γ, interferon-γ; Th2, T helper type 2; IgE, immunoglobulin E.