Myotonic_Dystrophy_Project_Presentation.pptx

About myotonic dystrophy

1. Myotonic Dystrophy An Overview of a Rare Genetic Disorder Presented by: Himanshu Kumar

2. Introduction • A genetic, progressive muscle disorder. • Causes weakness and prolonged muscle contractions. • Most common form of adult muscular dystrophy.

3. Types • Type 1 (DM1) – Steinert’s disease (more severe, earlier onset). • Type 2 (DM2) – Proximal myotonic myopathy (milder, later onset).

4. Causes & Genetics • Mutation in DMPK gene (DM1) or CNBP gene (DM2). • Autosomal dominant inheritance. • Expansion of CTG or CCTG repeats in DNA. DNA Repeat Expansion (CTG/CCTG)

5. Symptoms Overview • Muscle weakness (face, neck, arms, legs). • Myotonia (delayed relaxation after contraction). • Fatigue. • Cardiac issues (arrhythmias). • Cataracts. • Difficulty swallowing and breathing. • Cognitive and emotional issues. 1. Muscle Weakness 2. Myotonia (Delayed Relaxation) 3. Fatigue 4. Cardiac Arrhythmias 5. Cataracts 6. Breathing & Swallowing Issues 7. Cognitive / Emotional Problems

6. Complications • Heart problems (life-threatening). • Respiratory failure. • Difficulty during childbirth (congenital form). • Risk of diabetes and thyroid disorders.

7. Diagnosis Pathway • Clinical examination. • Genetic testing (DNA test for CTG/CCTG repeats). • Electromyography (EMG). • Family history. 1. Clinical Examination 2. Electromyography (EMG) 3. DNA Genetic Testing 4. Family History

8. Treatment & Management • No cure available. • Symptomatic treatment: - Medications for myotonia (e.g., mexiletine). - Pacemakers for heart issues. - Physical therapy, speech therapy. • Lifestyle: regular exercise, avoid stress. • Genetic counseling. 1. No Cure Available 2. Medications (e.g., Mexiletine) 3. Pacemakers for Heart Issues 4. Physical & Speech Therapy 5. Lifestyle Modifications 6. Genetic Counseling

9. Prognosis • Progressive condition with variable severity. • Lifespan may be shortened in severe DM1 cases. • Supportive care improves quality of life.

10. Research & Future • Gene therapy and RNA-based treatments under study. • Ongoing clinical trials for new medications.

11. Conclusion • Myotonic dystrophy is a genetic progressive disorder. • Early diagnosis and supportive care are vital. • Research offers hope for future therapies.

12. References • WHO and NIH medical resources. • Standard medical genetics textbooks. • Recent research publications.

13. History & Discovery • First described by Hans Gustav Wilhelm Steinert in 1909. • Recognized as a hereditary muscle disorder. • Genetic basis discovered in the 1990s with identification of DMPK gene mutation.

14. Epidemiology • Prevalence: ~1 in 8,000 people worldwide. • DM1 is more common than DM2. • Found across all ethnic groups. • Congenital form occurs in babies born to mothers with DM1. • Anticipation: severity increases and onset occurs earlier in successive generations.

15. Pathophysiology • Expanded CTG or CCTG repeats in DNA create toxic RNA. • This RNA traps RNA-binding proteins, disrupting normal cellular function. • Leads to widespread effects in muscle, heart, eye, and endocrine systems. • Explains the multi-system involvement of the disease.

16. Clinical Variants of DM1 • Congenital DM1: Severe, present at birth, breathing/swallowing difficulties. • Childhood-onset DM1: Learning difficulties, behavioral problems. • Adult-onset DM1: Muscle weakness, cataracts, cardiac issues. • Late-onset DM1: Mild symptoms, often cataracts and mild weakness.

17. Cardiac Involvement • Conduction abnormalities are common. • Risk of arrhythmias and sudden cardiac death. • Pacemaker or defibrillator may be needed. • Regular ECG monitoring is essential.

18. Respiratory Issues • Weakness of respiratory muscles. • Risk of hypoventilation and respiratory infections. • Sleep apnea is common. • Non-invasive ventilation (BiPAP) may be required.

19. Endocrine & Metabolic Effects • Insulin resistance and risk of diabetes. • Thyroid dysfunction. • Testicular atrophy and infertility in males. • Menstrual irregularities in females.

20. Supportive Care • Multidisciplinary approach: neurologist, cardiologist, pulmonologist, physiotherapist. • Regular monitoring of heart and lung function. • Cataract surgery if vision impaired. • Occupational therapy for daily living support. • Counseling and psychological support.

21. Genetic Counseling & Family Planning • Autosomal dominant inheritance: 50% chance of passing mutation. • Genetic counseling recommended for affected families. • Prenatal testing and preimplantation genetic diagnosis (PGD) are available. • Important for family planning decisions.