Duchenne's Muscular Dystrophy

Duchenne's Muscular Dystrophy
Contents:
1. Introduction
2. Causes
3. Dystrophin
4. Inheritance
5. Symptoms
6. Treatment
7. Complications and Treatment
8. Conclusion
9. References

1. Duchenne's Muscular Dystrophy Atul Adhikari Third Semester, B. Pharm. School of Health and Allied Sciences Pokhara University, Dhungepatan, Lekhnath-12, Kaski , Nepal

2. Contents Introduction Causes Dystrophin Inheritance Symptom Treatment Complications and Treatment Conclusion References

3. Introduction Duchenne's muscular dystrophy (DMD) is a genetic condition which affects the muscles, causing muscle weakness and can be inherited. It is a serious condition which starts in early childhood. It usually effects only boys, although girls may carry the Duchene gene.

4. The muscle weakness is mainly in the 'proximal' muscles, which are those near the trunk of the body, around the hips and the shoulders. This means that fine movements, such as those using the hands and fingers, are less affected than movements like walking. It starts in childhood and may be noticed when a child has difficulty standing up, climbing or running. 4 Duchenne's Muscular Dystrophy

5. Causes The cause is a genetic change. Muscles contain a protein (chemical) called dystrophin , which is necessary for muscles to function properly. People with DMD have a shortage of dystrophin in their muscles. The lack of dystrophin leads to muscle fibre damage and a gradual weakening of the muscles. The shortage of dystrophin is caused by a faulty gene. 5 Duchenne's Muscular Dystrophy

6. Dystrophin Dystrophin is a rod-shaped cytoplasmic protein, and a vital part of a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane. This complex is variously known as the costamere or the dystrophin -associated protein complex. Many muscle proteins, such as α- dystrobrevin , syncoilin , synemin , sarcoglycan , dystroglycan , and sarcospan , colocalize with dystrophin at the costamere . The Dystrophin gene is the longest human gene known on DNA level, 6 Duchenne's Muscular Dystrophy

7. 7 Duchenne's Muscular Dystrophy

8. Inheritance DMD is inherited in a pattern called 'X-linked inheritance Boys have one X chromosome and one Y chromosome; girls have two X chromosomes. The DMD gene is 'carried' by women, but does not usually cause problems in girls or women This is because of there being two X chromosomes in women: one X chromosome has the 'faulty' DMD gene, and the other X chromosome has a normal gene, which compensates for the faulty one.

9. B oys with the DMD gene do not have a second X chromosome and so they cannot compensate for the faulty gene. Therefore, boys with the DMD gene always have symptoms of the disease 9 Duchenne's Muscular Dystrophy

10. 10 Duchenne's Muscular Dystrophy

11. For a woman who carries the DMD gene, there is a 1 in 2 chance that her sons will have DMD, and a 1 in 2 chance that her daughters will carry the gene . 11 Duchenne's Muscular Dystrophy

12. Symptoms The muscle weakness is not noticeable at birth, even though the child is born with the gene which causes it. The weakness develops gradually. It usually shows up in early childhood. Symptoms are mild at first, but increase as the child gets older. 12 Duchenne's Muscular Dystrophy

13. The symptoms usually start around age 1-3 years. Parents may notice: Difficulty with walking, running, jumping and climbing stairs. Walking may look different with a 'waddling' type of walk. The boy may be late in starting to walk (although many children without DMD also walk late). When you pick the child up, you may feel as if he 'slips through your hands', due to looseness of the muscles around the shoulder. The calf muscles may look bulky, although they are not strong. 13 Duchenne's Muscular Dystrophy

14. As he gets older, the child may use his hands to help him get up, looking as if he is 'climbing up his legs'. This is called 'Gower's sign'. Some boys with DMD also have a learning difficulty. Usually this is not severe. Sometimes, a delay in development may be the first sign of DMD. The child's speech development may also be delayed. 14 Duchenne's Muscular Dystrophy

15. 15 Duchenne's Muscular Dystrophy

16. Diagnosis Diagnosis may be suspected because of the child's symptoms . When looking for signs of DMD, it is important to watch the child running and getting up from the floor - the muscle weakness is more noticeable during these activities. 16 Duchenne's Muscular Dystrophy

17. The first step in making the diagnosis is a blood test. This tests for creatine kinase . Children with DMD always have a very high level of creatine kinase (about 10-100 times normal). If the creatine kinase level is high, further tests are needed to see whether this is due to DMD or to some other condition. The next step in diagnosing DMD involves either a muscle biopsy and/or genetic tests: 17 Duchenne's Muscular Dystrophy

18. A muscle biopsy involves taking a small sample of a muscle, under local anaesthetic . The sample is examined under a microscope using special techniques to look at the muscle fibres and the dystrophin protein. Genetic tests are done using a blood sample. The DNA in the blood is tested to look at the dystrophin gene. This test can diagnose most cases of DMD. 18 Duchenne's Muscular Dystrophy

19. Treatment There is no cure for DMD at present. However, treatments can help according to complications observed. support may be needed for the legs and ankles and wheelchairs for late stages. Treatment with medication called 'corticosteroids' (or 'steroids') can help to maintain the child's muscle strength such as prednisolone or deflazacort. 19 Duchenne's Muscular Dystrophy

20. Child will need regular check-ups. This may involve different specialists, for example, heart and lung checks, orthopaedic care for bones and joints, physiotherapists, and dieticians. 20 Duchenne's Muscular Dystrophy

21. C omplications of Duchenne's muscular dystrophy and treatment Anesthetics People with DMD need extra care if they have a general anesthetic. Certain anesthetic medicines can cause a harmful reaction for people who have DMD. Also, extra care for the chest and breathing is needed. 21 Duchenne's Muscular Dystrophy

22. Osteoporosis People with DMD may develop osteoporosis (thinning of the bones). This is due to lack of mobility and also to steroid treatment. A good intake of vitamin D and calcium helps keep bones strong. These can be obtained from certain foods or from vitamin supplements, and by action of sunshine on the skin (which makes natural vitamin D). 22 Duchenne's Muscular Dystrophy

23. Joint and spinal complications Muscle weakness can result in some joints becoming tight - this is called a 'contracture'. This can be treated using orthotic devices (splints or casts). Curvature of the spine (scoliosis) can occur due to muscle weakness. The scoliosis can cause discomfort and is not helpful for posture and breathing. Treatments which can help are a spinal brace, or surgery to the spine. 23 Duchenne's Muscular Dystrophy

24. Nutrition and digestion Some children with DMD are prone to being overweight, especially if taking steroid treatment. Teenagers and adults with DMD may be underweight, due to loss of muscle bulk. Dietary advice can be helpful in these situations. Constipation can be a symptom for anyone who is not mobile. This can be treated with laxatives and a high fiber diet. 24 Duchenne's Muscular Dystrophy

25. In the later stages of DMD , people with DMD may have difficulty with chewing and swallowing food. They may need a careful assessment and nutritional advice or supplements. If the problem is severe, then a ' gastrostomy ' (a feeding tube into the stomach) may be needed. Chest and breathing complications the breathing muscles weaken, causing shallow breathing and a less effective cough mechanism. This can lead to chest infections, because mucus and bacteria are not cleared so easily from the chest. 25 Duchenne's Muscular Dystrophy

26. getting medical advice early and taking antibiotics where needed. Also, you will be offered immunization with influenza and pneumococcal vaccines, to help prevent chest infections. Physiotherapy can help to clear mucus from the chest. Cardiac (heart) complications Teenagers and adults with DMD may develop a heart problem called cardiomyopathy, which means weakness of the heart muscle Cardiomyopathy can be helped by medication. 26 Duchenne's Muscular Dystrophy

27. Conclusion DMD is a very serious condition in which the muscle weakness increases gradually over the years, complications eventually develop and it shorten life. The breathing or heart problems usually become more serious for older teenagers or people in their twenties and is major cause of death. At present, average life expectancy for people with DMD is 27 years 27 Duchenne's Muscular Dystrophy

28. THANK YOUU AND HAVE A GOOD DAY 28 Duchenne's Muscular Dystrophy