Cystic Fibrosis Condition

Cystic fibrosis is a genetic condition that is exhibited by an accumulation of thick and sticky mucus capable of damaging an individual’s body organs. The disorder is progressive and causes damages to the respiratory system and consequently causes severe digestive system problems.

1 a. Strand of DNA

Cystic fibrosis arises as a consequence of alterations in a particular gene; the Cystic Fibrosis Trans membrane Conductance Regulator (CFTR) within chromosome 7.The abnormality in the gene is caused by a deletion of three DNA bases, a codon, from the CTFR gene.

b. Transcription and Translation of Mutation

The deletion of the codon in the CTFR gene affects transcription since the replication of m RNA is based on the wrong code for the manufacture of protein as the RNA to the cytoplasm for the formation of a protein. During translation t RNA that matches the codon on the m RNA ends up changing the sequence of the protein and ends up in the condition.

c. Physical Symptoms and pathophysiology

The disorder affects the respiratory system causing physical symptoms such as a persistent cough that produces phlegm, wheezing, shortness of breath especially during exercises, a stuffy nose and sinuses as well as recurrent lung infections. The respiratory symptoms are caused by the blockage of the passageways responsible for carrying air into the lungs by the thick, sticky mucus associated with the disease. Other physical symptoms of the disorder related with the digestive system include constipation, the production of greasy and foul-smelling stools, a swollen abdomen, and nausea, loss of appetite and poor weight gain and delayed growth, especially in children. The digestive system problems occur as a result of the mucus blocking up the channels responsible for carrying the digestive enzymes produced by the pancreas to the digestive system. Consequently, the intestines cannot take in the essential nutrients in the food causing the digestive system problems.

d. Classification system

The classification system of Cystic Fibrosis is based on the problems caused by mutations on the production of the CFTR protein. The classification has identified five classes including the protein production and protein processing mutations, gating mutations, conduction mutations as well as insufficient protein mutations being mutations classes 1 to 5 respectively.(Sosnay et al., 2015).

e. Mutations causative for CF

More than 1700 mutations have been identified to cause various mutations in the CTFR gene. The most common mutation causative of CF is associated with protein processing (Wilschanski et al., 2011). It involves the removal of a single amino acid from the CTFR protein affecting the shape of the protein and consequently causing the protein to be disposed of by the cell.

2. Inheritance pattern for CF

CF is genetically passed down in families in an autosomal recessive arrangement. For an offspring to have the disorder; both copies of the genes in each cell must have mutations. That is, both the mother and the father must be carriers of the disorder by possession of a faulty CTRF gene, and this faulty gene must be passed down to the offspring. Variations in penetrance and expressivity are associated with Cystic Fibrosis. This means that some causal mutations may be indicated by complete clinical penetrance where other mutations in the same gene show low levels or incomplete penetrance. Additionally, mosaicism is not a factor of CF. Cystic fibrosis is expressed in offspring if he/she inherits two mutant genes, one from each parent. The possibility of a future offspring having CF is 0.25 through the inheritance of two mutant genes, one from each parent. There is a 0.25 probability of the children to be free from CF and 0.5 possibilities that the child will be carrier of the disorder.

3. Nursing problems

A CF patient faces various nursing problems such as an upsetting cough and wheeze as a result of dense mucus in the lungs. Malnutrition occurs due to the congestion of the digestive system by mucus. The mucus is responsible for blocking the ducts of the pancreas responsible for the production of enzymes responsible for digestion of food. The insufficient enzyme causes inefficient digestion of essential nutrients. Recurrent lung and chest infections such as pneumonia and bronchitis are caused by the building up of mucus in the lungs which act as a perfect breeding ground for the bacterial infections (Witt, 2003). The interventions to these nursing problems include medications such as antibiotics, steroids, and bronchodilator drugs among others which help in clearing and controlling infections within the digestive system and the lungs. The drugs help in the treatment of some of the health problems associated with the disorder. Physiotherapy is helpful for clearing the mucus that builds up in the lungs.

4. Testing of Minors

 Carrier testing for Jacob’s minor daughter is inappropriate. The access to such information should be restricted since the child will not realize any immediate medical benefit. Such tests could be deferred until the daughter is an adult to obtain patient informed consent (Ross et al., 2013). It is unethical to conduct tests without patient consent if the tests do not support immediate intervention in the case of serious illnesses for the minor patients.

5.

Information to the Extended Family

Information should be provided to Sarah and Jacob’s other family members regarding the CF diagnosis and the possibility that their offspring could be affected by the disorder. The potential is that the siblings of both Sarah and Jacob may be carriers of CF and these mutant genes may be passed down to their offspring hence the need for disclosure of information.

6. Risk of CF to Mr. & Mrs. G’s Unborn Child

The present diagnosis of Cystic Fibrosis in Mr. & Mrs. G’s eight-month-old son is an indication that both Sarah and Jacob are carriers of the disorder. Each of the parents has a mutant CFTR gene. The possibility that the unborn child could have Cystic Fibrosis is 25%. For the case to occur, the child must inherit one mutant gene from each of the parents. There is also a 25% chance that the child could be healthy without any genes for the disorder through the acquisition of normal genes from each of the parent. The likelihood that the child would be a carrier of the disease is 50% as a result of inheriting a mutant CFTR gene from either of the parents.

7. Pedigree

                                                                                                            C = normal gene

                                    Cc                                            Cc                    c =CF gene

   Cc                             Cc                                Cc                                cc

C-Normal Gene

C – CF gene

Unaffected                              CF Carrier                                                      CF

References

Ross, L. F., Saal, H. M., David, K. L., & Anderson, R. R. (2013). Technical report: ethical and policy issues in genetic testing and screening of children. Genetics in Medicine, 15(3), 234.

Sosnay, P. R., Siklosi, K. R., Van Goor, F., Kaniecki, K., Yu, H., Sharma, N., & Masica, D. L. (2013). Defining the disease liability of variants in the cystic fibrosis transmembrane conductance regulator gene. Nature genetics, 45(10), 1160.

Wilschanski, M., Miller, L. L., Shoseyov, D., Blau, H., Rivlin, J., Aviram, M., & Cohen-Cymberknoh, M. (2011). Chronic ataluren (PTC124) treatment of nonsense mutation cystic fibrosis. European Respiratory Journal, 38(1), 59-69.

Witt, H. (2003). Chronic pancreatitis and cystic fibrosis. Gut, 52(suppl 2), ii31-ii41.