cystic fibrosis_Abhishek kumar_2nd group.pptx

Cysitc fibrosis

1. Cystic Fibrosis Abhishek kumar Group :- 2nd semester :- 10th(6 ys program)

2. Introduction Cystic fibrosis  (also known as  CF  or  mucoviscidosis ) is a common recessive genetic disease . The name  cystic fibrosis  refers to the characteristic scarring (fibrosis) and cyst formation within the pancreas .  Difficulty breathing is the most serious symptom and results from frequent lung infections. CF is caused by a mutation in the gene for the protein cystic fibrosis transmembrane conductance regulator (CFTR). This gene is required to regulate the components of sweat,digestive juices, and mucus.

3. Introduction CF is most common among  Caucasians; one in 25 people of European descent carry one allele for CF. Individuals with cystic fibrosis can be diagnosed before birth by genetic testing , or by a sweat test in early childhood. It is caused by more than 1000 known mutation in CFTR gene , while 70% of the cases arise from deletion of Phe508 (∆F508 ) which is located in cytoplasmic domain of the CFTR protein .

4. HISTORY In 1938 Dorothy Hansine Andersen published an article, "Cystic Fibrosis of the Pancreas and Its Relation to Celiac Disease: She was the first to describe the characteristic cystic fibrosis of the pancreas and to correlate it with the lung and intestinal disease prominent in CF. She also first hypothesized that CF was a recessive disease and first used pancreatic enzyme replacement to treat affected children In 1988 the first mutation for CF, ΔF508 was discovered by Francis Collins, Lap- Chee Tsui and John R. Riordan on the seventh chromosome. In 1989 Lap- Chee Tsui led a team of researchers at the Hospital for Sick Children in Toronto that discovered the gene responsible for CF .  

5. Cystic Fibrosis .... Cystic fibrosis is a heterogeneous recessive genetic disorder with features that reflect mutations in the cystic fibrosis transmembrane conductance regulator ( CFTR ) gene . A thick, sticky mucus clogs the lungs and digestive system of people Individuals with defect in both copies of CFTR genes develop cystic fibrosis whereas single copy defect leads to be carrier of CF .

6. CFTR (Cystic fibrosis transmembrane conductance regulator ) Cystic fibrosis transmembrane conductance regulator (CFTR) is a protein that in humans is encoded by the  CFTR  gene. CFTR is a ABC transporter-class ion channel that transports chloride and thiocyanate ions across epithelial cell membranes. Mutations of the CFTR gene affect functioning of the chloride ion channels in these cell membranes, leading to cystic fibrosis and congenital absence of the vas deferens. Cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)

7. Cytogenetics of CFTR Park et al. (1987) concluded that CF is distal to and on the 5-prime side of MET. They determined this by in situ hybridization on metaphase and prometaphase chromosomes of normal lymphocytes as well as lymphoblastoid cells containing a t(5;7)(q35;q22). Normal cells showed clustering of MET grains to 7q31. In the course of studying a case of cystic fibrosis,  Spence et al. (1988)  discovered what appeared to be a case of uniparental disomy: the father did not contribute alleles to the propositus for markers near the CF locus or for centromeric markers on chromosome 7.

8. Structure of CFTR The CFTR gene contains about 170,000 base pairs. This gene encodes the instruction to build the CFTR protein. CFTR is a glycoprotein with 1480 amino acids. The protein consists of five domains. There are two transmembrane domains, each with six spans of alpha helices . These are each connected to a nucleotide binding domain (NBD) in the cytoplasm. The first NBD is connected to the second transmembrane domain by a regulatory "R" domain that is a unique feature of CFTR, not present in other ABC transporters . The ion channel only opens when its R-domain has been phosphorylated by PKA and ATP is bound at the NBDs. The carboxyl terminal of the protein is anchored to the cytoskeleton by a PDZ-interacting domain.

9. Structure of CFTR

10. CFTR (Cystic fibrosis transmembrane conductance regulator )

11. CFTR (Cystic fibrosis transmembrane conductance regulator ) Sequence:Chromosome : 7 ….CFTR in MapViewer

12. CFTR (Cystic fibrosis transmembrane conductance regulator ) SNP linked to Gene CFTR:--

13. CFTR (Cystic fibrosis transmembrane conductance regulator ) The similarity search of Human cystic fibrosis mRNA, encoding a presumed transmembrane conductance regulator (CFTR) by Basic Local Alignment Search Tool (89 BLAST)….. Remarkably another gene at chromosome No. 20 showing higher similarity with CFTR at chromosome No. 7.

14. CFTR (Cystic fibrosis transmembrane conductance regulator ) Some detail on the gene of chromosome no 20. showing higher similarity with CFTR at chromosome No. 7 in BlAST .

15. Function of CFTR CFTR functions as a cAMP-activated ATP-gated anion channel, increasing the conductance for certain anions (e.g. Cl-) to flow down theirelectrochemical gradient. ATP-driven conformational changes, which in other ABC proteins fuel uphill substrate transport across cellular membranes, in CFTR open and close a gate to allow transmembrane flow of anions down their electrochemical gradient. "Single CFTR channels open and close stochastically in an ATP-dependent manner, the open state catalyzing exclusively “downhill” Cl− movement at rates of millions of ions per second, orders of magnitude too high for any enzymatic pump cycle to support ". Essentially, CFTR is an ion channel that evolved as a 'broken' ABC transporter that leaks when in open conformation.

16. The CFTR is found in the epithelial cells of many organs including the lung, liver, pancreas, digestive tract, reproductive tract, and skin. Normally, the protein moves  chloride  and thiocyanate  ions (with a negative charge) out of an epithelial cell to the covering mucus . This results in an electrical gradient being formed and in the movement of (positively charged) sodium ions in the same direction as the chloride via a paracellular pathway. Due to this movement, the water potential of the mucus is reduced, resulting in the movement of water here by osmosis and a more fluid mucus In sweat glands, CFTR defects result in reduced transport of sodium chloride and sodium thiocyanate  in the reabsorptive duct and saltier sweat. This was the basis of a clinically important sweat test for cystic fibrosis before genetic screening was available. Function of CFTR

17. Protein Structure and Function CFTR transports chloride ions (Cl-) ions across the membranes of cells in the lungs, liver, pancreas, digestive tract, reproductive tract, and skin. CFTR is made up of five domains: two membrane-spanning domains (MSD1 and MSD2) that form the chloride ion channel two nucleotide-binding domains (NBD1 and NBD2) that bind and hydrolyze ATP (adenosine triphosphate) and a regulatory (R) domain. Delta F508, the most common CF-causing mutation, occurs in the DNA sequence that codes for the first nucleotide-binding domain (NBD1). Side chain and backbone contributions of Phe508 to CFTR folding.

18. Protein Structure and Function Conserved domains of cystic fibrosis   transmembrane conductance regulator [Homo sapiens]

19. Types of mutations in CFTR

20. Changes in Protein structure CFTR functions principally as a cAMP-induced chloride channel and appears capable of regulating other ion channels. Besides the most common mutation, ΔF508, accounting for about 70% of CF chromosomes worldwide, more than 850 mutant alleles have been reported to the CF Genetic Analysis Consortium. These mutations affect CFTR through a variety of molecular mechanisms which can produce little or no functional CFTR at the apical membrane

21. 3D Image of Protein When a CFTR protein with the delta F508 mutation reaches the ER, the quality-control mechanism of this cellular component recognizes that the protein is folded incorrectly and marks the defective protein for degradation. As a result, delta F508 never reaches the cell membrane. People who are homozygous for delta F508 mutation tend to have the most severe symptoms of cystic fibrosis due to critical loss of chloride ion transport. This upsets the sodium and chloride ion balance needed to maintain the normal, thin mucus layer that is easily removed by cilia lining the lungs and other organs. The sodium and chloride ion imbalance creates a thick, sticky mucus layer that cannot be removed by cilia and traps bacteria, resulting in chronic infections.

22. Characterization of cystic fibrosis Classic cystic fibrosis is characterized by chronic bacterial infection of the airways and sinuses, fat maldigestion due to pancreatic exocrine insufficiency, infertility in males due to obstructive azoospermia, and elevated concentrations of chloride in sweat. Patients with nonclassic cystic fibrosis have at least one copy of a mutant gene that confers partial function of the CFTR protein, and such patients usually have no overt signs of maldigestion because some pancreatic exocrine function is preserved

23. Signs and Symptoms An individual born with the cystic fibrosis gene will usually be diagnosed in the first year, although occasionally symptoms do not become evident until adolescence, or even later. The symptoms and their severity vary from person to person, but may include: Excessive salt in sweat, dehydration ,Chronic cough, possibly with blood streaking,Wheezing,Frequent Bronchitis and other airway infections,Thick mucus secretions in the lungs,Chronic sinusitis,Asthma,Nasal polyps (growths inside the nose),Failure to put on weight,abdominal swelling, pain and flatulence,Frequent, foul-smelling stools,Failure of newborn to pass stoo,Fatigue Late onset of puberty, inflammation of the pancreas, cirrhosis (a liver condition), and infertility may also be associated with cystic fibrosis.

24. Signs and Symptoms

25. LUNG Lung disease results from clogging of the airways due to mucus build-up, decreased  mucociliary clearance and resulting inflammation. Inflammation and infection will cause injury and structural changes to the lungs, leading to a variety of symptoms. In the early stages, incessant coughing, copious phlegm production, and decreased ability to exercise are common.

26. LUNG Other symptoms include coughing up blood (hemoptysis), high blood pressure in the lung (pulmonary hypertension), heart failure, difficulties getting enough oxygen to the body (hypoxia), and respiratory failure requiring support with breathing masks such as bilevel positive airway pressure machines or ventilators. In later stages, changes in the architecture of the lung such as pathology in the major airways ( bronchiectasis ) further exacerbate difficulties in breathing.

27. Lung Infection Staphylococcus aureus ,  Haemophilus influenzae , and  Pseudomonas aeruginosa  are the three most common organisms causing lung infections in CF patients . In addition to typical bacterial infections, people with CF more commonly develop other types of lung disease. Among these is allergic broncho pulmonary aspergillosis , in which the body's response to the common fungus Aspergillus fumigatus  causes worsening of breathing problems .   .

28. G I tract Intestinal abnormality Meconium ileus Distal intestinal obstruction syndrome (DIOS) Rectal prolapse Hepatobiliary disease Focal biliary cirrhosis Multilobular cirrhosis Pancreatic endocrine dysfunction Cystic fibrosis related diabetes colonoscopy for distal intestinal obstruction syndrome in cystic fibrosis patients

29. ENDOCRINE The pancreas contains the islets of Langerhans , which are responsible for making insulin, a hormone that helps regulate blood glucose . Damage of the pancreas can lead to loss of the islet cells , leading to a type of diabetes that is unique to those with the disease. This cystic fibrosis related diabetes (CFRD) shares characteristics that can be found in Type 1  and Type 2  diabetics, and is one of the principal non-pulmonary complications of CF.  Vitamin D is involved in calcium and phosphate regulation. Poor uptake of vitamin D from the diet because of malabsorption can lead to the bone disease osteoporosis  in which weakened bones are more susceptible to fractures .  In addition, people with CF often develop clubbing of their fingers and toes due to the effects of chronic illness and low oxygen in their tissues.

30. INFERTILITY   A ffects both men and women. At least 97% of men with cystic fibrosis are infertile, but not sterile and can have children with assisted reproductive techniques. These men make normal sperm  but are missing the tube (vas deferens), which connects the testes to the ejaculatory ducts of the penis .Many men found to have congenital absence of the vas deferens during evaluation for infertility have a mild, previously undiagnosed form of CF.  Some women have fertility difficulties due to thickened cervical mucus or malnutrition. In severe cases, malnutrition disrupts ovulation and causes amenorrhea. Intracytoplasmic sperm injection can be used to provide fertility for men with cystic fibrosis

31. Treatment of other aspects Newborns with CF typically require surgery, whereas adults with distal intestinal obstruction syndrome typically do not. Treatment of pancreatic insufficiency by replacement of missing digestive enzymes allows the duodenum to properly absorb nutrients and vitamins that would otherwise be lost in the feces. So far, no large-scale research involving the incidence ofatherosclerosis and coronary heart disease in adults with cystic fibrosis has been conducted. This is likely due to the fact that the vast majority of people with cystic fibrosis do not live long enough to develop clinically significant atherosclerosis or coronary heart disease.

32. Treatment of other aspects Diabetes is the most common non-pulmonary complication of CF. It mixes features of type 1 and type 2 diabetes, and is recognized as a distinct entity, cystic fibrosis-related diabetes(CFRD). While oral anti-diabetic drugs are sometimes used, the only recommended treatment is the use of insulin injections or an insulin pump, and, unlike in type 1 and 2 diabetes, dietary restrictions are not recommended.

33. Treatment of other aspects Development of osteoporosis can be prevented by increased intake of vitamin D and calcium , and can be treated by bisphosphonates , although adverse effects  can be an issue. Poor growth may be avoided by insertion of a feeding tube for increasing calories  through supplemental feeds or by administration of injected growth hormone. Sinus infections are treated by prolonged courses of antibiotics. The development of nasal polyps or other chronic changes within the nasal passages may severely limit airflow through the nose, and over time reduce the patient's sense of smell. Sinus surgery is often used to alleviate nasal obstruction and to limit further infections. Nasal steroids such as fluticasone are used to decrease nasal inflammation.

34. Treatment of other aspects Gene Therapy has made massive advances in the way that cystic fibrosis has been treated throughout the world. With the help of the Cystic Fibrosis Trust , which has a league of highly professional gene therapists, both somatic and Adeno-associated viral vector have made advances. The Adenoviridae , or more commonly known as the cold virus, is genetically altered, allowing the 'thin mucus gene' to enter lung cells. They are currently stage 3 /Clinical_trial , and following the success of these trials, the treatment can become readily available and valid in the eyes of the medical world. Male infertility caused by absence of the vas deferens may be overcome with testicular sperm extraction (TEST), collecting sperm cells directly from the testicles. If the collected sample contains too few sperm cells to likely have a spontaneous fertilization,  intracytoplasmic sperm injection can be performed. Female infertility may be overcome by assisted reproduction technology, particularly embryo transfer  techniques.

35. Gene Therapy and cystic fibrosis Recombinant adeno-associated viral vectors (rAAV)-mediating gene-targeting approaches used to generate new cystic fibrosis ferret and pig models. Schematic representation of the mechanism of gene targeting using rAAV. Target sequence homology (blue) and a selectable marker (red) are packaged between two AAV inverted terminal repeats (ITRs). Following infection, homologous recombination between the rAAV vector and the target genomic locus mediates insertion of the selectable marker. ( b ) Design of rAAV vectors used to disrupt the coding sequence of the  CFTR  gene through targeted insertion of a neomycin expression cassette in exon 10. ( c ) Design of rAAV vectors used to delete the F508 codon in exon 10 of the  CFTR  gene. In this approach, the neomycin expression cassette is inserted into intron 11 of the CFTR  gene.

36. Treatment of cystic fibrosis in Herbal Medicine Herbs beneficial to cystic fibrosis patients include: To help break down mucus: Thyme (thymus vulgaris ), Indian tobacco (lobelia inflata ), anise ( pimpinella anisum ), hyssop ( hyssopus officinalis ), licorice root ( glycyrrhiza glabra ), rosemary ( rosemarinus officinalis ) For acute infection: Coneflower ( echinacea purpurea ), goldenseal ( hydrastis canadensis ), thyme (thymus vulgaris ), wild indigo ( baptisia tinctoria )

37. Treatment of cystic fibrosis in Homeopathic medicine Remedies which may be prescribed for cystic fibrosis patients include: Antimonium tart - for rattling, unproductive cough Carbo vegetabilis  - for difficulty breathing Laurocerasus  - for collapsed lung

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