On the other hand, cystic fibrosis is much more prevalent in white individuals. And in the US. One out of 20 White individuals are living with the heterozygous genotype for this particular condition. So what exactly is cystic fibrosis? So just like PKU and stickle cell anemia, cystic fibrosis is an autosomal recessive disease. So an individual will have the disease and will show it if they are homozygous recessive.