Fig. 2From: Population monitoring of trisomy 21: problems and approachesa Prevalence of Down syndrome (DS) in the 10 Omani regions from 2000 to 2004 per 10,000 newborns. Three different clusters could be identified: (red) highest, (dark yellow) middle, (blue) lowest DS birth prevalence/10,000 newborns. b DS sex ratio of the 3 cluster, c DS prevalence per 10,000 newborns for each region, assigned to the three clusters. The lines represent the mean value. The differences are highly significant (p < 0.0001; after [49], modified)Back to article page