Cystic Fibrosis Gene Therapy | Recombinant DNA Technology

Since there is at present no effective treatment for most genetic disorders, the role lies mainly in the prevention of such conditions through genetic counselling or gene advice and recombinant DNA (deoxyribonucleic acid) technology.

Cystic Fibrosis Mutation

Genetic advice: Autosomal recessive traits such as cystic fibrosis (CF) affect both males and females. Unlike dominant, traits are manifest only in the homozygous state i.e., in those individuals who possess a double dose of mutant gene. Heterozygotes who possess only one mutant gene are usually perfectly healthy.
Similarly offspring of an affected person are usually healthy, because most recessive conditions are so rare that it would be most unlikely that an affected person would marry a female who is heterozygous for the same mutant gene.

Characteristically in recessive traits, affected individuals cannot be traced from one generation to the next and if more than one member of a family is affected they are usually siblings.
When dealing with rare recessive disease like cystic fibrosis, the parents of affected individuals are often found to be related.

Cystic Fibrosis Diagnosis

Antenatal diagnosis: Family limitation is not the only course of action open to parents who are at high risk, other possibilities are

  • Artificial insemination by healthy donor (if father is affected).
  • Antenatal diagnosis with selective abortion of affected fetus.

Cystic Fibrosis Gene Therapy

  • There is little doubt that recombinant DNA technology has made considerable impact on the clinical application of genetics.
  • It will help us to understand more about the molecular basis of disease and its prevention through antenatal diagnosis.
  • Further more treatment of autosomal recessive diseases (cystic fibrosis) by direct replacement of defective genes may soon become a reality.
  • There is also possibility of developing pre-symptomatic treatment for those who are healthy but would otherwise develop a genetic disorder.

Recombinant DNA technology

  • Introduction of genetic engineering or more precisely recombinant DNA technology which consists of generating fragments of DNA containing specific genes (autosomol recessive like cystic fibrosis) of interest.
  • This is done by using enzymes called as restriction endonucleases which cleave DNA at sequence specific sites.
    These fragments are incorporated into the DNA of a vector. This is the recombinant part of the process. The vector is then introduced into a microbial host, usually E. coli, which is grown in culture to produce clones with multiple copies of incorporated gene.
  • By Southern blot method, this gene can be labelled. This technique can be applied for synthesis of biologically important molecules (such as human insulin, growth hormone etc.) and carrier detection.