<Tr> <Td> All others </Td> <Td> 27.5% </Td> </Tr> <P> Cystic fibrosis is the most common life - limiting autosomal recessive disease among people of European heritage . In the United States, about 30,000 individuals have CF; most are diagnosed by six months of age . In Canada, about 4,000 people have CF . Around 1 in 25 people of European descent, and one in 30 of Caucasian Americans, is a carrier of a CF mutation . Although CF is less common in these groups, roughly one in 46 Hispanics, one in 65 Africans, and one in 90 Asians carry at least one abnormal CFTR gene . Ireland has the world's highest prevalence of CF, at one in 1353 . </P> <P> Although technically a rare disease, CF is ranked as one of the most widespread life - shortening genetic diseases . It is most common among nations in the Western world . An exception is Finland, where only one in 80 people carries a CF mutation . The World Health Organization states, "In the European Union, one in 2000--3000 newborns is found to be affected by CF". In the United States, one in 3,500 children is born with CF . In 1997, about one in 3,300 Caucasian children in the United States was born with CF . In contrast, only one in 15,000 African American children suffered from it, and in Asian Americans, the rate was even lower at one in 32,000 . </P> <P> Cystic fibrosis is diagnosed in males and females equally . For reasons that remain unclear, data have shown that males tend to have a longer life expectancy than females, but recent studies suggest this gender gap may no longer exist perhaps due to improvements in health care facilities, while a recent study from Ireland identified a link between the female hormone estrogen and worse outcomes in CF . </P>

Which of the following type of activity is defective in a person with cystic fibrosis