MS4A2 and asthma: Hakonarson and Wjst (2001) reviewed > 150 linkage, association, and candidate gene studies collectively and report approximately 500 asthma and atopy loci identified across the genome, and additional gene identification continues to arise beyond these regions (Cookson 2003; Hakonarson et al. 2002; Holgate et al. 2003; Howard et al. 2003; Vercelli 2003; Weiss and Raby 2004).