Scientists have identified novel loci or locus, a specific position on a chromosome where a particular gene or genetic marker is located, that may contribute to the success of asthma treatment in children of African descent. An African study, conducted by Victor Ortega and colleagues from Mayo Clinic, Arizona, US, identified two loci associated with a better response to a 5.0 times higher fluticasone dose combined with salmeterol than to the original low-dose fluticasone. One was located on chromosome 6 and mapped to two intronic variants within the SYCP2L gene and the other was on chromosome 12 and mapped to variants adjacent to RNFT2 and NOS1.

The study, published in The Lancet Children & Adolescent Health, reportedly drew on data from 249 children aged 5-11 and 267 adolescents and adults aged 12-69 years and had asthma.  The study also noted that the randomised crossover trials showed no overall association between African ancestry (at least one grandparent) and treatment response, but did reveal a potential association between a higher proportion of African ancestry and increased risk of asthma exacerbations.