Current research on cystic fibrosis gene therapy suggests that it will become an important treatment strategy
Cystic fibrosis is an autosomal recessive disease, triggered by mutation in the gene CFTR i.e. cystic fibrosis transmembrane conductance regulator.
CFTR is an ABC gene i-e ATP-binding cassette (transporter) gene that encodes a protein. This CFTR protein is a chloride ion channel protein that controls the flow of chloride ions and water across the cells. This movement is important in generating sweat, digestive juices, as well as mucus secretion and its clearance.
This CFTR gene is located at q 31.2 locus of chromosome 7 long arm. The most common mutation in cystic ...view middle of the document...
e. decreased chloride secretion and increased sodium absorption, resulting in impaired mucociliary clearance.
PATTERN OF INHERITANCE:
Pattern of inheritance is an autosomal recessive disease. Cystic fibrosis develops when both alleles inherited from parents cannot produce normal functioning CFTR protein. If both the parents are unaffected carriers then chances of their child to develop cystic fibrosis are one in four (affected), while the chances of unaffected carrier children are two in four and of unaffected child are one in four. This shows autosomal pattern of inheritance.
SIGNS AND SYMPTOMS:
Patients with genetic defect of CFTR gene mainly present respiratory infections, starting from accumulation of thick and sticky mucus and impaired clearance leading to pneumonia, bronchiectasis causing pulmonary hypertension and eventually, heart failure.
These infections of the respiratory tract become chronic and irreversible sometimes, with more than 90% patients dying due to respiratory failure. These patients have poor growth and weight despite of normal food intake as digestion is also impaired due to lack of digestive enzymes and juices. Absorption of minerals and vitamins is impaired as well.
Cystic fibrosis, besides respiratory system, also affects pancreas which in turn cause diabetes. It also affects liver, kidney and intestines, causing impaired clotting, cirrhosis (nodular) of liver and malabsorption. Patients with cystic fibrosis may be infertile, especially males as they congenitally lack vas deferens and have sperm with low motility rate, whereas in females, infertility is due to thickened cervical mucus and malnutrition, leading to ovulatory failure and finally amenorrhea.
TREATMENT AND MANAGEMENT:
Management strategies that should be adopted to improve the life expectancy of patients of cystic fibrosis include the proactive treatments of respiratory tract infections and pulmonary rehabilitation mainly, as well as good and healthy diet and an active lifestyle. Quality of life of patients with cystic fibrosis should be maintained by limiting and treating secondary bacterial infections of respiratory tract.
Nowadays, the treatment and management plan for the patients of cystic fibrosis is multidisciplinary, as the disease involves multi organs like lungs, gastro intestinal tract, and reproductive organs. As most of the damage is to lungs, the main target therapy is for lungs, including antibiotics and chest physiotherapy that uses percussive methods. The aim behind these chest percussive therapies and mechanical techniques is to dislodge mucus plugs and clear the airway.
Ivafactor is a medicine recently approved for the treatment of cystic fibrosis. Aerosolized medications i.e. Dornase Alfa, hypertonic saline are used. Often, when the disease worsens mechanical breathing support (ventilator) is also required, and if mechanical breathing support fails then lung transplantation becomes necessary. Care must be taken as both...