CBR1 and Down syndrome: These findings are important since there are wide variations in CBR1 activity between individuals, in disease and after consumption of a number of naturally occurring CBR1 inhibitors: human tissue CBR1 expression and activity varies significantly between ethnic groups6; CBR1 expression and activity is increased in Down’s syndrome due to the location of the CBR1 gene on chromosome 2148; CBR1 inhibitors such as flavonoids and polyphenols are present in many foods and supplements49 and reported enhancers of CBR1 activity include components of cigarette smoke7.