Cystic Fibrosis  (cc)
    is a recessive GENETIC DISEASE of childhood that is characterized by
    respiratory & digestive problems and is usually fatal.  The average life span of 
    its victims is only about 32 years. 
       Effects include heavy production of thick mucus in respiratory tracts, which increases
       susceptibility to respiratory infections;  90 percent of all patients die of chronic lung disease.
       Secretions that block pancreatic ducts cause important digestive enzymes to fail to reach the
       small intestine.  Treatment is directed toward relief of symptoms, and no cure is yet known.

Cystic fibrosis apparently is caused by the inability of chloride ions to cross the specialized epithelial cells of salivary, mucus, and sweat glands and the pancreas.  The ductal systems become clogged with thick secretions.  Cystic fibrosis is a recessive condition from a mutation to a single gene, which produces a disfunctional chloride channel protein.   

 

 

 

 

 

Gene lies on Chromosome 7
      CFTR gene : cystic fibrosis transmembrane conductance regulator
          mutation:   ΔF508 ; deletion of 3 nucelotides at positions 507-508 in the CFTR protein

   A
 U       ISOLEUCINE 506
 C
   A
 U      ISOLEUCINE 507
 C                                   -->    ISOLEUCINE  507      
   U                                              
 U      PHENYLALANINE 508    -->    NO 508
 U                                                                    code
   G
 G      GLYCINE 509   
 U
 G
 U      VALINE 510
 U

           
            

 

 

 

 

 

 

 

The disease is a commonly inherited disease among Caucasians: 

1 / 2,500  have the disease      cc      (0.0004 %)   

How many carriers  [Cc]  are there is U.S. population?

                do the math now.......

 

 

 

 

 

 

 

 

 

 

 

 

frequency of cc  is   0.0004     [1/2,500  =  0.0004]

            thus freq of   "c"  is   sq.root of  0.0004   =  0.02
  
            if       freq  of c  =  0.02 then freq of C =  1 - 0.02  =  0.98
  
            then   freq of  2(Cc) =  2 (.98) (.02)   =   0.039%

4% of American whites are asymptomatic carriers...
                     4 out of 100 whites are carriers     (Cc) 
                     1 out of 25 in U.S. Caucasian population carry gene for cf
     

 

 

 

 

charles mallery
college of arts and sciences
university of miami
coral gables, fl 33124
cmallery@miami.edu
 © 2006        updated 03/30/2007