GLCCI1 rs37973 does not influence treatment response to inhaled corticosteroids in white subjects with asthma

To The Editor: Inhaled corticosteroids (ICS) are the primary anti-inflammatory therapy for the control and management of asthma, but their effects are characterised by some inter-individual variability that may have a genetic basis1–4. Identification of genetic markers that predict ICS treatment response will facilitate individualised treatment for asthma patients in the future, particularly in those with more severe disease. An association between genetic variation in GLCCI1 and response to ICS therapy in non-Hispanic white asthma subjects was observed by Tantisira et al.5 Genome wide association analysis of 118 trios (one asthmatic child and two parents) from the NHLBI Childhood Asthma Management Program (CAMP) identified 13 single nucleotide polymorphisms (SNPs) with evidence for association with the level of ICS treatment response. These 13 SNPs which included the GLCCI1 promoter polymorphism rs37972, were genotyped and evaluated in four additional independent collections: adult studies SOCS (Salmeterol Or CorticosteroidS) and SLIC (SalmeteroL ± Inhaled CorticosteroidS) (n=264); a second adult study (n=385); LOCCS (Leukotriene modifier Or Corticosteroid or Corticosteroid-Salmeterol) (n=185) and CARE (Childhood Asthma Research and Education) (n=101). In three of the four replicate populations GLCCI1 rs37973, a functional promoter polymorphism5 in complete linkage disequilibrium with rs37972 in white populations, was associated (P