Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

[EX Q]: Context: The median income for a household in the city in 2000 was $29,378 (2010$37,436), and the median income for a family was $41,158. Males had a median income of $32,929 versus $26,856 for females. The per capita income for the city was $17,076. About 20.2% of families and 25.9% of the population were below the poverty line, including 41.5% of those under age 18 and 5.6% of those age 65 or over. 
 Question: What group of people made up the largest percentage of those below the poverty line?
[EX A]: under age 18

[EX Q]: Context: Recent genome-wide association studies (GWAS) for Caucasians identified several allelic variants associated with increased risk of developing restless legs syndrome (RLS), also known as Willis-Ekbom disease. Although the pathogenic mechanisms of RLS are not entirely understood, it is becoming increasingly evident that many diseases such as RLS can be attributed to an epistasis. The study objectives were to evaluate whether the associations of RLS with all loci determined in previous GWAS for Caucasians can be replicated significantly for the Korean population and to elucidate whether an epistasis plays a role in the pathogenesis of RLS. DNA from 320 patients with RLS and 320 age- and sex-matched controls were genotyped for variants in the RLS loci. A significant association was found for rs3923809 and rs9296249 in BTBD9 (P < 0.0001 and P = 0.001, respectively); the odds ratio (OR) for rs3923809 was 1.61 (P < 0.0001) to 1.88 (P < 0.0001) and the OR for rs9296249 was 1.44 (P = 0.001) to 1.73 (P = 0.002), according to the model of inheritance. The OR for the interaction between rs3923809 in BTBD9 and rs4626664 in PTPRD was 2.05 (P < 0.0001) in the additive model, 1.80 (P = 0.002) in the dominant model and 2.47 (P = 0.004) in the recessive model. There was no significant association between genotypes of all tested single nucleotide polymorphisms and the mean value of serum iron parameters. Our results suggest that the role of BTBD9 in the pathogenesis of restless legs syndrome is more universal across populations than previously reported and more efforts should be focused on the role of epistasis in the genetic architecture of restless legs syndrome. 
 Question: Willis-Ekbom disease is also known as?
[EX A]: restless legs syndrome

[EX Q]: Context: Sigma Editions is an independent record label founded in 1998 by Rosy Parlane and Dion Workman (both ex-members of Thela). 
 Question: What year was Sigma Editions created in?
[EX A]:
1998