1.Hereditary diseaseshttps://apnacare.me/?p=485
Hereditary diseases are medical conditions passed from generation to generation via genetic material commonly known as DNA. The various diseases result due to anomalies found in the person’s genome such as mutations occurring in one, multiple genes or structural abnormalities that occur in a chromosome. Summary of hereditary diseases:
Types of Hereditary Diseases
Single-Gene Disorders
Caused by a mutation in one gene.
Examples:
Cystic Fibrosis: Affects the respiratory and digestive systems.
Sickle Cell Anemia: Red blood cells become misshaped.
Huntington’s Disease: Degenerative brain disease characterized by loss of control of movement and thought processes.
Chromosomal Disorders
Result from changes in the structure or number of chromosomes.
Examples:
Down Syndrome: An extra copy of chromosome 21 (trisomy 21).
Turner Syndrome: Missing one X chromosome in females.
Klinefelter Syndrome: Extra X chromosome in males (XXY).
Polygenic or Multifactorial Disorders
Involves mutations in multiple genes, often influenced by environmental factors.
Examples:
Diabetes: Type 1 and Type 2.
Heart Disease: Genetic predisposition along with lifestyle factors.
Some Cancers: Such as breast cancer (BRCA1/BRCA2 mutations).
Mitochondrial Disorders
Result from mutations in mitochondrial DNA, which is inherited exclusively from the mother.
Examples:
Leber’s Hereditary Optic Neuropathy: Affects vision.
Mitochondrial Myopathy: Leads to muscle weakness.
Inheritance Patterns
Autosomal Dominant: A mutation in one gene is enough to cause the disease (e.g., Huntington’s disease).
Autosomal Recessive: Two mutated copies of a gene are required (e.g., cystic fibrosis).
X-Linked: Tied to genes on the X chromosome; effects males more severely (e.g., hemophilia).
Mitochondrial Inheritance: Given through maternal lineage.
Diagnosis and Management
Genetic Testing: Depicts mutations linked with hereditary diseases.
Family History Assessment: Assesses risk according to familial patterns.
Prenatal Testing: To identify disorders in fetuses as early as possible, such as amniocentesis.
Lifestyle Changes: Minimize risk for multicausal disorders, such as proper diet and exercise.
Gene Therapy: Experimental therapies that modify genes to prevent or treat diseases.
Prevention and Counseling
Genetic Counseling: Provides a better understanding of one’s risk, allowing them to make informed decisions about reproduction.
Carrier Screening: Tests if individuals are carriers of certain hereditary disorders.
Preimplantation Genetic Diagnosis (PGD): Screening of embryos for genetic abnormalities in IVF.
2.Cystic Fibrosis:
Cystic Fibrosis, also known as CF, is a genetic disorder that affects lungs, digestive organs, and sometimes other organs of the body by producing thick mucus. It can block the airways and ducts due to which very serious respiratory and digestive problems can occur.
Major Characteristics of Cystic Fibrosis
Causes:
This disease is caused by mutations in the CFTR gene, which is known as Cystic Fibrosis Transmembrane Conductance Regulator.
The most common mutation is ΔF508, which causes the production of a defective CFTR protein.
Inheritance Pattern:
Autosomal recessive: An individual must inherit two copies of the defective gene (one from each parent) to have the disease.
Carriers (with one defective gene) usually do not manifest symptoms.
Primary Effects:
Lungs: The accumulation of mucus causes frequent lung infections, chronic coughing, and decreased lung function.
Digestive System: Mucus fills the pancreatic ducts, preventing digestive enzymes from being secreted into the intestine to break down nutrients.
Other Organs: May also involve the liver, sinuses, and reproductive organs.
Symptoms
Persistent coughing with mucus.
Frequent lung infections (such as bronchitis or pneumonia).
Shortness of breath or wheezing.
Poor growth and weight gain despite good nutrition.
Greasy, bulky stools due to malabsorption.
Salty-tasting skin because of abnormal salt regulation in sweat.
Infertility in males because of blockage or absence of the vas deferens.
Diagnosis
Newborn Screening: Finds CFTR mutations early.
Sweat Test: Determines the amount of salt in sweat; high amounts suggest CF.
Genetic Testing: Finds particular mutations in the CFTR gene.
Pulmonary Function Tests (PFTs): Determine lung capacity and effectiveness.
Treatment and Management
Though there is no cure for CF, treatment centers around alleviating symptoms and enhancing quality of life:
Respiratory Therapies
Airway Clearance Techniques: Facilitate mucus loosening and removal
Bronchodilators: Relax airways to ease breathing.
Inhaled Antibiotics: Prevent and treat lung infections.
Medications:
CFTR Modulators: ivacaftor (Kalydeco), elexacaftor-tezacaftor-ivacaftor (Trikafta) enhances CFTR protein function
Mucolytics: breaks down mucus, dornase alfa
Digestive Support:
Pancreatic Enzyme Replacement Therapy (PERT): helps with digestion
Vitamin Supplements: supplement deficiencies (A, D, E, K)
Lifestyle and Nutrition:
High-calorie, high-fat diet to help meet energy needs
Regular exercise to improve lung function
Advanced Treatments:
Lung Transplant: patients with severe lung damage.
Gene Therapy: Experimental approaches aim to correct CFTR mutations.
Prognosis
Advances in treatments, including CFTR modulators, have significantly improved the life expectancy and quality of life for individuals with CF.
Many people with CF now live into their 40s and beyond, depending on disease severity and access to care.
3.Sickle Cell Anemia
Sickle Cell Anemia (SCA) is a hereditary blood disorder characterized by the production of abnormal hemoglobin called hemoglobin S. This condition affects the shape and function of red blood cells, leading to various health complications.
Main Features of Sickle Cell Anemia
Cause:
The cause is a mutation in the HBB gene, which carries instructions for making hemoglobin.
Hemoglobin S makes red blood cells stiff and crescent or sickle shaped when oxygen is low.
Inheritance Pattern
Autosomal recessive: One must inherit two copies of the sickle cell gene-one from each parent-to develop the disease.
Carriers (with one sickle cell gene) have sickle cell trait, which is usually asymptomatic but may confer some protection against malaria.
Direct Effects:
Sickle-shaped cells cause an obstruction in small vessels, which results in pain and organ damage.
Sickle cells break easily, resulting in anemia because of a lack of red blood cells.
Chronic Symptoms
Fatigue or weakness (due to anemia).
Pale or yellowish skin (jaundice).
Shortness of breath.
Pain Episodes (Crises):
Abrupt and intense pain resulting from obstructed blood flow.
It typically occurs in the chest, abdomen, and joints.
Complications:
Splenomegaly leading to infections.
Stroke resulting from the obstruction of blood flow to the brain.
Acute chest syndrome: A severe lung complication that can be fatal.
Delayed growth and puberty in children.
Vision impairment due to the destruction of blood vessels in the eyes.
Diagnosis
Newborn Screening: Hemoglobin abnormalities are detected through routine blood test.
Blood Tests:
Hemoglobin Electrophoresis: The presence of hemoglobin S is confirmed.
Complete Blood Count: Measures the level of anemia.
Genetic Tests: Identify gene mutations in HBB.
Management and Treatment
Though there isn’t a complete cure, different treatments are to manage symptoms and complications and ultimately enhance quality life:
Medicines:
Hydroxyurea: Cuts down episodes of pain crisis and blood transfusions.
Analgesics: Pain management in crisis.
L-Glutamine: Known as Endari, an oral drug reducing oxidative stress along with pain crisis.
Blood Transfusions: Prevents acute complications such as stroke and provides relief in very severe anemia.
Bone Marrow (Stem Cell) Transplant:
An effective treatment for SCA, although only available as a matched donor and only for the most severe forms of SCA.
Preventive Measures:
Vaccines: Against infections
Penicillin Prophylaxis: Prevent bacterial infections in young children
Routine check-ups (such as a transcranial Doppler ultrasound if risk).
Lifestyle and Support:
Drink lots of water to avoid dehydration and sickling
Avoid extreme temperature and high altitudes
Engage in moderate exercise while being careful not to cause overexertion
Prognosis
Improved treatments have increased the life expectancy of patients with SCA to often beyond their 40s.
Quality of life varies depending on the severity of the disease, access to care, and adherence to treatment.
4.Huntington’s Disease:
Huntington’s Disease (HD) is a progressive, hereditary neurodegenerative disorder that affects the brain, leading to motor, cognitive, and psychiatric impairments. It is caused by a genetic mutation that leads to the production of an abnormal protein, which gradually damages nerve cells.
Key Features of Huntington’s Disease
Cause:
HD is caused by a mutation in the HTT gene, which provides instructions for making the huntingtin protein.
The mutation involves an abnormal expansion of CAG trinucleotide repeats in the HTT gene.
More than 40 repeats typically cause the disease, with earlier onset linked to a higher number of repeats.
Inheritance Pattern:
Autosomal dominant: A person needs only one copy of the defective gene to inherit the disease.
Each child of an affected parent has a 50% chance of inheriting the mutation.
Pathophysiology
The abnormal huntingtin protein accumulates in brain cells, which disrupts normal function and causes neuronal death, especially in the basal ganglia and cortex.
Symptoms
Motor Symptoms
Involuntary movements (chorea): jerky, dance-like movements
Muscle rigidity or stiffness (dystonia).
Difficulty coordinating and balancing
Problems with swallowing and speech
Cognitive Symptoms
Impaired memory and judgment.
Difficulty concentrating and multitasking.
Progressive dementia.
Psychiatric Symptoms
Depression and anxiety.
Irritability, aggression, or apathy.
Obsessive-compulsive behaviors.
Psychosis (rare).
Course
Over time, the symptoms worsen, usually within 10-20 years.
Late stages involve severe motor disability, inability to speak or care for oneself, and profound cognitive decline.
Genetic Testing
Positive test that determines the presence of the CAG repeat expansion in the HTT gene.
Neurological Examination
Investigates symptoms related to the motor, cognitive, and psychiatric areas.
Imaging Tests
Advanced stages may exhibit brain atrophy, especially within the basal ganglia, via MRI or CT scans.
Treatment and Management
There is no known cure for Huntington’s Disease, but treatments are instead focused on treating symptoms and improving the quality of life:
Drug Medication
Tetrabenazine (Xenazine) or Deutetrabenazine (Austedo): Therapy to reduce chorea.
Antipsychotics (For example olanzapine or risperidone): Treating psychiatric symptoms and chorea
Antidepressants such as SSRIs: To treat depression and anxiety
Mood Stabilizers like valproic acid: Stabilizes mood swings and irritability
Therapies
Physical therapy: Reduces falls and improves mobility.
Speech therapy: Helps in communication and issues with swallowing
Occupational therapy: Supports daily living tasks
Support Lifestyle:
Nutritional support to overcome dysphagia and weight loss.
Care plan with established routines of cognitive and behavioral treatment.
Experimental Therapies:
Gene-Silencing Therapies: Experimental therapies include ASOs, designed to decrease the expression of the mutant huntingtin protein.
Stem Cell Therapy: Researchers are working on replacing the lost neurons.
Prognosis
Huntington’s Disease is a progressive and ultimately fatal disease. In general, life expectancy is between 10 and 30 years after symptom onset.
Complications, such as pneumonia, infections, or choking, are common causes of death.