BSC SEM 4 UNIT 4 PATHOLOGY 2 & GENETICS.

🌿 Genetic Conditions of Adolescents and Adults

Genetic conditions are inherited or caused by mutations in genes or chromosomes. They can manifest in adolescence or adulthood, even if the individual appeared healthy at birth.

🔹 Common Genetic Conditions in Adolescents & Adults:

Condition	Description	Onset	Key Features
Huntington’s Disease	Autosomal dominant neurodegenerative disorder	Usually 30–50 years	Involuntary movements, mood changes, cognitive decline
Marfan Syndrome	Connective tissue disorder (autosomal dominant)	Late childhood/adolescence	Tall stature, long limbs, heart valve issues, aortic aneurysm risk
Familial Hypercholesterolemia (FH)	Defect in LDL receptor gene	Late adolescence to adulthood	Extremely high cholesterol, early heart disease
Hereditary Breast & Ovarian Cancer Syndrome (BRCA1/2)	Mutation increases risk of breast, ovarian, prostate cancers	Early adulthood onwards	Family history of early cancers
Polycystic Kidney Disease (ADPKD)	Genetic disorder causing kidney cysts (autosomal dominant)	Adolescence or early adulthood	Hypertension, kidney failure risk
Neurofibromatosis Type 1 & 2	Tumor suppressor gene mutation	Childhood to adulthood	Skin changes, neurofibromas, learning disabilities
Hemochromatosis	Autosomal recessive iron overload disorder	Adulthood (30–50 years)	Fatigue, liver cirrhosis, skin pigmentation
Thalassemia Major/Intermedia	Hemoglobinopathy (recessive)	Adolescence (delayed growth, anemia)	Anemia, iron overload, skeletal deformities
Adult-Onset Tay-Sachs	Rare variant of Tay-Sachs	20s–30s	Neurological decline, psychiatric symptoms

🧬 Genetic Nursing: Role & Responsibilities

Genetic nursing focuses on the care of individuals and families affected by genetic conditions or at risk of them. It integrates genomics, counseling, prevention, and supportive care into nursing practice.

🩺 Key Roles of the Genetic Nurse:

1. Assessment:

Obtain a detailed family history (pedigree over 3 generations)
Identify hereditary patterns (e.g., autosomal dominant/recessive, X-linked)
Monitor for early signs of genetic conditions
Evaluate psychosocial and emotional impact

2. Genetic Counseling Support:

Explain the nature of the genetic disorder in simple terms
Provide pre- and post-test education related to genetic testing
Support decision-making (e.g., testing, treatment, family planning)
Refer to genetic counselors and specialized services

3. Genetic Testing Coordination:

Educate on types of genetic tests (diagnostic, predictive, carrier testing)
Obtain informed consent for testing
Ensure confidentiality and ethical handling of results

4. Education & Advocacy:

Provide information on the condition, inheritance, and lifestyle modifications
Empower patients with knowledge for self-care and family care
Promote non-discrimination (e.g., educate on GINA – Genetic Information Nondiscrimination Act, US context)

5. Preventive & Supportive Care:

Coordinate screening and surveillance (e.g., annual MRIs, cancer screenings)
Address reproductive options (e.g., prenatal diagnosis, PGD, IVF)
Offer psychological support for coping, stigma, and familial implications

6. Interdisciplinary Collaboration:

Work closely with geneticists, counselors, social workers, and physicians
Develop personalized care plans based on genetic risk and condition

✨ Special Considerations in Genetic Nursing

Area	Considerations
Ethical Issues	Privacy, informed consent, risk of stigmatization, right to know/not know
Cultural Sensitivity	Beliefs about inheritance, religious views, reproductive decisions
Legal Issues	Confidentiality, discrimination laws, legal implications of testing
Psychosocial Support	Mental health support, family communication, support groups

🧠 Example Nursing Diagnoses Related to Genetic Conditions:

Risk for Ineffective Coping related to new diagnosis of genetic disorder
Decisional Conflict regarding genetic testing results
Knowledge Deficit related to inheritance pattern and disease progression
Anxiety related to potential transmission of a genetic disorder to offspring

🧬 Cancer Genetics: Familial Cancer Overview

🔹 What is Cancer Genetics?

Cancer genetics studies how changes or mutations in genes contribute to the development of cancer. Some cancers occur due to inherited genetic mutations, increasing a person’s lifetime risk of specific cancers—this is known as familial or hereditary cancer.

👨‍👩‍👧‍👦 Familial (Hereditary) Cancer

✅ Definition:

Familial cancer refers to cancer that runs in families due to inherited mutations in specific genes. It accounts for about 5–10% of all cancers.

🔎 Key Characteristics:

Early age of onset (before 50 years)
Multiple affected relatives (especially first-degree relatives)
Multiple cancers in the same individual
Specific cancer types clustering in families
Bilateral or multiple primary tumors

🧬 Common Hereditary Cancer Syndromes:

Syndrome	Gene(s) Involved	Cancers Associated	Inheritance Pattern
Hereditary Breast & Ovarian Cancer Syndrome (HBOC)	BRCA1, BRCA2	Breast, ovarian, prostate, pancreatic	Autosomal Dominant
Lynch Syndrome (HNPCC)	MLH1, MSH2, MSH6, PMS2	Colorectal, endometrial, ovarian, stomach	Autosomal Dominant
Li-Fraumeni Syndrome	TP53	Breast, sarcoma, brain tumors, leukemia	Autosomal Dominant
Familial Adenomatous Polyposis (FAP)	APC	Colorectal (hundreds of polyps), stomach, thyroid	Autosomal Dominant
Multiple Endocrine Neoplasia (MEN)	MEN1, RET	Pituitary, parathyroid, adrenal, thyroid cancers	Autosomal Dominant
Cowden Syndrome	PTEN	Breast, thyroid, endometrial	Autosomal Dominant

🩺 Role of Genetic Nursing in Familial Cancer

1. Risk Assessment:

Take a detailed 3-generation family history (pedigree)
Identify patterns of cancer in the family (age, type, number of relatives)
Use risk tools (e.g., Gail Model, BOADICEA, Manchester scoring system)

2. Education and Counseling Support:

Explain inheritance patterns, cancer risks, and prevention strategies
Educate on available genetic testing (e.g., BRCA test, panel tests)
Help patients understand test results (positive, negative, VUS)

3. Genetic Testing:

Assist in informed consent before testing
Coordinate testing with physicians and genetic counselors
Address emotional concerns, implications for children and family

4. Surveillance and Preventive Strategies:

Monitor for early signs of cancer (screening protocols)
Educate on preventive options:
- Lifestyle changes (diet, smoking cessation)
- Medications (e.g., tamoxifen for BRCA+ women)
- Prophylactic surgery (e.g., mastectomy, oophorectomy)

5. Psychosocial & Ethical Support:

Support patients in disclosing risk to relatives
Address anxiety, guilt, and coping challenges
Ensure privacy/confidentiality of genetic information
Advocate against genetic discrimination

🧠 Sample Nursing Diagnoses for Familial Cancer:

Risk for Anxiety related to uncertainty about genetic test results
Decisional Conflict related to choices about genetic testing or surgery
Knowledge Deficit regarding hereditary cancer risks and surveillance
Ineffective Family Coping related to shared genetic risk

📘 Case Example:

Patient: 32-year-old woman with a strong family history of breast and ovarian cancer
Intervention:

Nurse collects a 3-generation pedigree
Educates patient on BRCA testing
Coordinates referral to genetic counselor
Discusses surveillance (mammograms, MRIs), and preventive surgery
Provides ongoing emotional support

🧬 Inborn Errors of Metabolism (IEMs)

✅ Definition:

Inborn errors of metabolism are rare genetic disorders caused by enzyme defects that lead to abnormal metabolism of proteins, carbohydrates, or fats. These defects result in the accumulation of toxic substances or deficiency of vital compounds in the body.

🧪 Types of IEMs:

Category	Examples	Metabolic Problem
Amino acid disorders	Phenylketonuria (PKU), Maple Syrup Urine Disease (MSUD), Homocystinuria	Defective amino acid metabolism
Carbohydrate disorders	Galactosemia, Hereditary Fructose Intolerance, Glycogen Storage Diseases	Inability to process sugars
Fatty acid oxidation disorders	Medium-chain acyl-CoA dehydrogenase deficiency (MCADD)	Energy production failure during fasting
Organic acidemias	Methylmalonic acidemia, Propionic acidemia	Accumulation of toxic organic acids
Urea cycle disorders	Ornithine transcarbamylase deficiency	Ammonia accumulation
Lysosomal storage disorders	Tay-Sachs, Gaucher’s disease, Niemann-Pick	Toxic storage in cells
Mitochondrial disorders	MELAS, Leigh syndrome	ATP production affected

🧠 Clinical Features:

Symptoms may appear in neonatal period, infancy, or childhood, but some may present in adolescence or adulthood.

🚨 Common Signs:

Poor feeding
Vomiting
Failure to thrive
Lethargy or coma
Seizures
Developmental delay
Unusual urine/body odor
Hepatomegaly
Hypoglycemia
Metabolic acidosis
Hyperammonemia

🧬 Diagnosis of IEMs:

Test Type	Purpose
Newborn screening	Detects metabolic disorders early (heel prick test)
Plasma amino acids / Urine organic acids	Identifies metabolic block
Enzyme assay	Detects deficient enzymes
Molecular genetic testing	Confirms mutation in a specific gene
Blood gases, ammonia, lactate, glucose	Evaluates metabolic crisis

🩺 Nursing Responsibilities in IEMs:

1. Early Detection and Monitoring:

Recognize early signs of metabolic decompensation
Support newborn screening follow-up
Monitor for hypoglycemia, acidosis, dehydration

2. Nutritional Management:

Administer special diets (low-protein, lactose-free, fructose-free, etc.)
Prevent catabolism during illness (provide IV glucose)
Educate families on lifelong dietary restrictions

3. Emergency Management:

Manage acute metabolic crisis (IV fluids, correction of acidosis, dialysis if needed)
Prevent prolonged fasting
Administer medications (e.g., L-carnitine, ammonia scavengers)

4. Family Support and Education:

Teach parents about dietary guidelines, emergency signs, medication use
Discuss genetic counseling and prenatal testing for future pregnancies
Refer to metabolic specialists, dietitians, and support groups

5. Developmental Surveillance:

Regularly assess growth and development
Refer for speech therapy, physiotherapy, occupational therapy if delays present

🧠 Nursing Diagnoses for IEMs:

Risk for Imbalanced Nutrition related to metabolic restrictions
Ineffective Coping related to chronic illness in child
Knowledge Deficit regarding special diet and emergency care
Risk for Delayed Development related to disease complications
Risk for Infection due to metabolic instability and hospitalization

📝 Example: Phenylketonuria (PKU)

Deficiency of enzyme phenylalanine hydroxylase
Leads to accumulation of phenylalanine, which is toxic to the brain
Managed with low-phenylalanine diet
Newborn screening detects it early
If untreated → intellectual disability, seizures, behavioral issues

📘 Key Nursing Interventions:

Goal	Nursing Action
Prevent metabolic crisis	Ensure regular feeding, avoid fasting, administer prescribed supplements
Nutritional education	Guide parents on safe foods, formula use, food weighing
Family empowerment	Offer emotional support, connect with genetic counselors
Development monitoring	Track milestones, refer for interventions

🧬 Blood Group Alleles: Genetics & Inheritance

✅ What are Blood Group Alleles?

Blood groups are determined by genes that code for specific antigens on red blood cells (RBCs). The most clinically important blood group systems are:

1. ABO Blood Group System

Controlled by the ABO gene on chromosome 9.
There are three alleles:
- A (produces A antigen)
- B (produces B antigen)
- O (no antigen – nonfunctional protein)
Inheritance follows Mendelian codominance: GenotypePhenotypeAA / AOABB / BOBABABOOO

2. Rh Factor (Rhesus system)

Controlled by the RHD gene on chromosome 1.
Rh positive (Rh+) = presence of D antigen
Rh negative (Rh–) = absence of D antigen
Inherited in an autosomal dominant pattern:
- Rh+/Rh+ or Rh+/Rh– = Rh positive
- Rh–/Rh– = Rh negative

🧪 Clinical Importance of Blood Group Genetics

Blood Transfusions: Incompatible transfusions cause hemolytic reactions.
Pregnancy & Hemolytic Disease of the Newborn (HDN): Rh– mothers carrying Rh+ babies may develop antibodies causing Rh incompatibility in future pregnancies.
Organ Transplants: ABO compatibility is crucial for transplant success.
Forensic/Parentage testing: ABO typing can help exclude biological relationships.

🧬 Genetic Disorders Related to Blood Group Alleles or Blood Genetics

Though ABO and Rh alleles themselves don’t cause disease, some genetic blood disorders have hereditary patterns and may co-relate with blood typing during diagnosis or transfusion compatibility.

🔹 Examples of Genetic Disorders in Adolescents and Adults Related to Blood Genetics:

Disorder	Inheritance	Description	Age of Onset
Sickle Cell Anemia	Autosomal recessive (HBB gene)	RBCs become sickle-shaped → anemia, pain crises	Childhood to adolescence
Thalassemia Major / Intermedia	Autosomal recessive (HBA or HBB gene)	Defective hemoglobin → anemia, organ damage	Childhood to adulthood
Hemophilia A & B	X-linked recessive (F8/F9 gene)	Impaired blood clotting → bleeding risk	Adolescence if mild
Hereditary Spherocytosis	Autosomal dominant	RBC membrane defect → hemolytic anemia, splenomegaly	Early childhood or adolescence
Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD)	X-linked recessive	Hemolysis after infections or drugs	Childhood to adulthood
Paroxysmal Nocturnal Hemoglobinuria (PNH)	Acquired mutation (not inherited)	Hemolytic anemia, blood clots, dark urine	Young adulthood

👩‍⚕️ Genetic Nursing in Blood-Related Disorders

Key Nursing Roles:

Family History Assessment: Check for patterns of anemia, bleeding, or early transfusions.
Genetic Counseling: For carriers (e.g., sickle cell trait, thalassemia trait).
Testing & Interpretation:
- Hemoglobin electrophoresis
- Gene mutation analysis
- Prenatal testing for carrier couples
Patient Education:
- Avoid triggers (e.g., fava beans in G6PD)
- Importance of regular transfusions or chelation therapy
- Pre-marital screening (especially in high-risk populations)
Transfusion Management:
- Ensure blood group compatibility
- Watch for alloimmunization
- Use extended phenotype matching in chronic transfusion cases

🧠 Nursing Diagnoses (Examples):

Risk for Imbalanced Fluid Volume related to hemolysis
Ineffective Health Maintenance related to genetic disease
Knowledge Deficit regarding inheritance and prevention
Risk for Bleeding (in hemophilia, thalassemia)
Fatigue related to chronic anemia

🌍 Public Health & Genetic Screening

Some countries have premarital or newborn screening programs for:

Sickle Cell Trait
Thalassemia
G6PD Deficiency

Blood typing is also essential in maternal care (Rh incompatibility prevention with Rhogam injections for Rh– mothers).

🩸 Hematological Disorders: Genetic Causes in Adolescents & Adults

✅ Definition:

Hematological disorders affect the blood and blood-forming organs (bone marrow, spleen, lymph nodes). Some are genetically inherited and present in adolescence or adulthood due to defective genes controlling hemoglobin, clotting factors, enzymes, or RBC structure.

🧬 Major Genetic Hematological Disorders

Disorder	Gene Involved	Inheritance Pattern	Age of Onset	Key Features
Sickle Cell Disease	HBB	Autosomal Recessive	Childhood → Adolescence	Anemia, vaso-occlusive crises, pain, infections
Thalassemia Major/Intermedia	HBA or HBB	Autosomal Recessive	Early childhood → Adulthood	Severe anemia, bone deformities, growth delay
Hemophilia A/B	F8 / F9	X-linked Recessive	Adolescence (mild forms)	Prolonged bleeding, joint hemorrhages
G6PD Deficiency	G6PD gene	X-linked Recessive	Adolescence → Adulthood	Hemolysis after drugs/infections/fava beans
Hereditary Spherocytosis	ANK1, SPTA1, etc.	Autosomal Dominant (mostly)	Childhood → Adolescence	Hemolytic anemia, jaundice, splenomegaly
Fanconi Anemia	DNA repair genes (FANCA, etc.)	Autosomal Recessive	Adolescence	Bone marrow failure, leukemia risk, skeletal anomalies
Paroxysmal Nocturnal Hemoglobinuria (PNH)	PIGA mutation (acquired)	Not inherited	Adolescence/Adulthood	Dark urine, thrombosis, fatigue
Hereditary Hemochromatosis	HFE gene	Autosomal Recessive	Adulthood (30–50 years)	Iron overload, liver damage, skin darkening

🧪 Clinical Manifestations by System

System	Symptoms
Blood	Anemia, fatigue, pallor, bruising, prolonged bleeding
Musculoskeletal	Joint pain (hemarthrosis in hemophilia), bone deformities (thalassemia)
Skin	Jaundice, dark urine (PNH, G6PD), hyperpigmentation (hemochromatosis)
CNS	Stroke (sickle cell), confusion in iron overload
GI/Liver	Hepatosplenomegaly, cirrhosis (hemochromatosis)
Growth/Development	Delayed milestones, short stature (Fanconi, Thalassemia)

🧬 Diagnosis of Genetic Hematological Disorders

Investigation	Purpose
CBC with peripheral smear	Check anemia, RBC shape
Hemoglobin Electrophoresis	Diagnose sickle cell, thalassemia
Clotting profile (PT, aPTT)	Hemophilia screening
Enzyme assay (G6PD)	Detect enzyme deficiency
Iron studies	Diagnose hemochromatosis
Genetic testing	Confirm mutation
Bone marrow biopsy	Fanconi anemia, leukemia suspicion

👩‍⚕️ Nursing Role in Genetic Hematological Disorders

1. Assessment & Monitoring:

Monitor for fatigue, pallor, jaundice, bleeding episodes
Assess family history and genetic patterns
Monitor for complications (stroke, organ damage)

2. Education:

Explain disease nature, inheritance, and prognosis
Teach trigger avoidance (e.g., fava beans for G6PD, alcohol/iron-rich foods for hemochromatosis)
Educate about bleeding precautions (for hemophilia)

3. Therapeutic Support:

Administer transfusions and monitor for reactions
Give chelation therapy for iron overload (Deferoxamine)
Support prophylactic clotting factors (in hemophilia)
Pain management (esp. in sickle cell crises)

4. Psychosocial Support:

Address body image concerns, especially in teens
Help manage school and peer challenges
Offer genetic counseling for affected individuals and carriers

5. Rehabilitation & Preventive Care:

Promote vaccinations (especially in splenectomized patients)
Screen regularly for organ complications
Coordinate with hematologists, dietitians, counselors

🧠 Common Nursing Diagnoses:

Risk for Bleeding (Hemophilia, Sickle Cell)
Fatigue related to chronic anemia
Impaired Growth and Development (Thalassemia, Fanconi)
Ineffective Health Maintenance related to poor understanding of disease
Risk for Infection (especially post-splenectomy or in anemia)

📌 Example: Case Study Snippet

Patient: 16-year-old male with known Hemophilia A presents with swollen right knee after football injury.

Nursing Actions:

Administer prescribed Factor VIII
Apply ice packs and elevate limb
Educate patient on activity restrictions
Monitor for signs of bleeding and joint damage

🧬 Genetic Hemochromatosis (GH)

✅ Definition:

Genetic Hemochromatosis is an autosomal recessive disorder in which the body absorbs too much iron from the diet, leading to progressive iron overload and damage to organs such as the liver, heart, pancreas, joints, and skin.

🔍 Cause & Genetics:

Feature	Details
Gene involved	HFE gene, especially C282Y and H63D mutations
Chromosome	Chromosome 6p
Inheritance	Autosomal recessive – both parents must pass on a defective copy
Pathophysiology	Mutation leads to reduced hepcidin (iron-regulating hormone), causing increased intestinal iron absorption and iron accumulation in tissues

🧪 Types of Hereditary Hemochromatosis:

Type	Gene	Typical Onset	Notes
Type 1 (Classic)	HFE	Adulthood (40–60 yrs)	Most common type
Type 2 (Juvenile)	HJV or HAMP	Adolescence	Severe, early organ damage
Type 3	TFR2	20–30 years	Less common
Type 4	SLC40A1 (Ferroportin Disease)	Adulthood	Autosomal dominant

👩‍⚕️ Clinical Features (Usually After Age 40 in Men, 50 in Women)

System	Symptoms
General	Fatigue, weakness
Skin	Bronze/gray discoloration (“bronze diabetes”)
Hepatic	Hepatomegaly, cirrhosis, ↑ liver enzymes
Pancreas	Diabetes mellitus due to β-cell damage
Cardiac	Arrhythmias, cardiomyopathy
Musculoskeletal	Joint pain, arthritis (esp. MCP joints)
Sexual	Decreased libido, impotence, hypogonadism

🧪 Diagnosis

Test	Purpose
Serum ferritin	Elevated in iron overload
Transferrin saturation	>45% suggests iron overload
Serum iron + TIBC	High iron, low TIBC
Liver function tests (LFTs)	Check liver involvement
Genetic testing	Confirms HFE mutation
Liver biopsy/MRI	Assess iron in liver, fibrosis/cirrhosis

🩺 Management & Treatment

Intervention	Details
Therapeutic Phlebotomy	Mainstay treatment – weekly blood removal lowers iron stores
Chelation Therapy	For patients who can’t undergo phlebotomy (e.g., anemia) – e.g., Deferoxamine
Low-iron Diet	Avoid iron-rich foods (red meat, liver), vitamin C (increases absorption)
Avoid Alcohol	Reduces liver damage risk
Regular Monitoring	Ferritin, liver enzymes, blood glucose, ECG
Liver transplant	In case of end-stage liver failure

👩‍⚕️ Nursing Responsibilities in GH

🔹 Assessment:

Assess for early signs: fatigue, skin changes, joint pain
Review family history of GH, liver disease, diabetes

🔹 Care During Phlebotomy:

Monitor vital signs
Ensure hydration before/after procedure
Watch for hypotension or dizziness

🔹 Patient Education:

Importance of lifetime monitoring
Teach dietary changes (avoid iron supplements, alcohol, raw seafood)
Educate about genetic testing for family members

🔹 Psychosocial Support:

Address anxiety or guilt over genetic diagnosis
Support family communication
Refer to genetic counselor if needed

🧠 Nursing Diagnoses Examples:

Fatigue related to systemic iron overload
Risk for Liver Dysfunction related to iron accumulation
Knowledge Deficit regarding dietary and treatment requirements
Ineffective Health Maintenance related to lack of follow-up or lifestyle changes
Risk for Sexual Dysfunction related to hypogonadism

📌 Key Points Summary

Early detection is crucial to prevent irreversible organ damage.
Men are more symptomatic earlier due to lack of iron loss from menstruation.
Therapeutic phlebotomy is highly effective and can restore life expectancy to normal if started early.
Family screening is essential in first-degree relatives.

🧠 Huntington’s Disease (HD)

✅ Definition:

Huntington’s Disease is a progressive, inherited neurodegenerative disorder characterized by movement abnormalities, psychiatric disturbances, and cognitive decline.
It is caused by a genetic mutation and usually manifests in adulthood, though a juvenile form can occur.

🧬 Genetic Basis of Huntington’s Disease

Feature	Details
Gene	HTT gene on chromosome 4
Mutation	Expansion of CAG trinucleotide repeat
Normal repeats	<26 repeats = normal
Premutation (intermediate)	27–35 repeats = no symptoms but risk for offspring
Affected	≥36 repeats = risk of disease (≥40 = full penetrance)
Protein involved	Abnormal huntingtin protein → toxic to brain cells
Inheritance	Autosomal dominant (only one mutated gene copy needed)
Anticipation	Each generation may show earlier onset & worse severity (especially when inherited from father)

📅 Onset of Symptoms

Type	Age of Onset	Notes
Adult-onset HD	30–50 years	Most common
Juvenile HD	<20 years	Rare, faster progression, seizures more common

🧠 Clinical Features

Domain	Symptoms
Motor	Chorea (involuntary jerky movements), dystonia, unsteady gait, rigidity (later stages), difficulty speaking/swallowing
Cognitive	Memory loss, poor judgment, difficulty concentrating, executive dysfunction
Psychiatric	Depression, anxiety, irritability, aggression, psychosis, apathy
Other	Weight loss, fatigue, sleep disturbance, suicidal thoughts

🧪 Diagnosis of Huntington’s Disease

Test	Purpose
Genetic testing	Confirms expanded CAG repeats in HTT gene
Family history	Strong clue due to dominant inheritance
MRI/CT brain	Shows atrophy of caudate nucleus and cortex
Neuropsychological testing	Assesses cognitive decline
Psychiatric evaluation	Diagnoses mental health complications

Presymptomatic Testing: Available for at-risk individuals with a family history, but requires genetic counseling due to emotional, ethical, and life planning implications.

⏳ Course of Disease

Progressive decline over 10–30 years
Late-stage complications: pneumonia, falls, aspiration, leading to death
No cure – management is supportive and symptomatic

💊 Management

Treatment Type	Intervention
Pharmacological	– Tetrabenazine (for chorea)

Antipsychotics (e.g., risperidone, olanzapine)
Antidepressants (SSRIs)
Benzodiazepines (for anxiety) | | Non-pharmacological | – Speech therapy
Physical and occupational therapy
Nutritional support
Counseling and social support |

👩‍⚕️ Nursing Considerations in Huntington’s Disease

🔹 Assessment & Monitoring:

Observe for motor changes, weight loss, aspiration risk
Assess mood, mental status, suicidal ideation
Monitor caregiver burden

🔹 Patient Education:

Discuss genetic inheritance and family planning
Educate about medications and therapy goals
Stress importance of multidisciplinary care

🔹 Support & Advocacy:

Provide emotional support for patient and family
Refer to genetic counselors and support groups
Assist with legal and ethical planning (advanced directives, power of attorney)

🧠 Nursing Diagnoses Examples:

Impaired Physical Mobility related to chorea and muscle rigidity
Risk for Aspiration related to swallowing difficulties
Disturbed Thought Processes related to cognitive decline
Risk for Caregiver Role Strain
Ineffective Coping related to progressive degenerative disease

👨‍👩‍👧 Genetic Implications for Family Members

Each child of an affected parent has a 50% chance of inheriting the disease.
Presymptomatic testing is available for adult children if desired (requires extensive counseling).
Ethical concerns include:
- Psychological distress
- Discrimination (insurance, employment)
- Reproductive decisions

📌 Summary: Key Points

Huntington’s is a fatal, autosomal dominant, neurodegenerative disease
Caused by CAG repeat expansion in the HTT gene
Onset typically in mid-adulthood; no cure, but symptoms manageable
Involves motor, cognitive, and psychiatric symptoms
Requires comprehensive nursing, psychosocial, and genetic support

🧠 Mental Illness & Genetics

✅ Overview:

Mental illnesses such as depression, bipolar disorder, schizophrenia, ADHD, and autism spectrum disorders have a strong genetic component. Although no single gene causes mental illness, a combination of genetic, environmental, and neurochemical factors contribute to the development of psychiatric conditions.

🧬 Genetics of Mental Illness

🔹 How Genetics Play a Role:

Mechanism	Example
Polygenic inheritance	Most mental illnesses are influenced by multiple genes (e.g., schizophrenia, depression)
Single-gene mutations	Seen in rare syndromes like Fragile X, Rett syndrome
Chromosomal abnormalities	Associated with autism, intellectual disability (e.g., 22q11.2 deletion in schizophrenia)
Gene-environment interaction	Stress + genetic vulnerability → onset of mental illness
Epigenetic changes	Gene expression altered by trauma, stress, or substance use

👥 Genetic Mental Health Disorders in Adolescents & Adults

Disorder	Genetic Basis	Age of Onset	Features
Schizophrenia	Polygenic, 22q11.2 deletion, DISC1 gene	Late adolescence/early adulthood	Delusions, hallucinations, disorganized thought
Bipolar Disorder	Polygenic, CACNA1C gene, ANK3 gene	Late teens–20s	Mood swings between mania and depression
Major Depressive Disorder (MDD)	Polygenic, SLC6A4 gene (serotonin transporter)	Adolescents–adults	Persistent sadness, hopelessness, fatigue
Autism Spectrum Disorder (ASD)	Multiple gene mutations, CNVs, fragile X syndrome	Childhood onset	Social deficits, repetitive behavior
Attention Deficit Hyperactivity Disorder (ADHD)	Dopamine transporter gene (DAT1), DRD4	School age → adulthood	Inattention, hyperactivity, impulsivity
Obsessive-Compulsive Disorder (OCD)	Polygenic, serotonin transporter gene	Adolescence–early adulthood	Obsessions, compulsions
Alzheimer’s Disease (Early-onset)	APP, PSEN1/2 mutations	Adults (30–60 years)	Memory loss, cognitive decline
Huntington’s Disease	CAG repeat expansion in HTT gene	30s–50s	Movement + psychiatric + cognitive decline
Fragile X Syndrome	FMR1 gene mutation	Adolescents	Anxiety, social deficits, intellectual disability
Rett Syndrome	MECP2 mutation (X-linked)	Early childhood (girls)	Regression, seizures, hand-wringing behavior

🧪 Diagnostic Tools

Tool	Purpose
Family history	First-degree relatives with mental illness = higher risk
Genetic testing	For known syndromes (e.g., Fragile X, 22q11.2 deletion)
Neuroimaging (MRI, fMRI)	Brain volume changes, connectivity abnormalities
Psychological evaluation	Structured interviews, rating scales (e.g., PHQ-9, YMRS)
Cognitive testing	Assess memory, attention, executive function

👩‍⚕️ Role of the Nurse in Genetic Mental Illnesses

🔹 1. Assessment & Risk Identification:

Take detailed family history (3-generation pedigree)
Screen for early signs of psychiatric symptoms
Observe for neurodevelopmental delays

🔹 2. Genetic Counseling Referral:

For families with heritable conditions (Fragile X, HD, ASD)
Discuss options for prenatal or preimplantation genetic testing

🔹 3. Patient and Family Education:

Teach about genetic risks and recurrence
Clarify that genes are a risk factor, not a destiny
Discuss environmental management (stress, substance use)

🔹 4. Supportive Care:

Promote medication adherence
Educate on early intervention
Provide emotional support to caregivers and families
Address stigma and discrimination

🧠 Common Nursing Diagnoses:

Impaired Social Interaction related to autistic traits or schizophrenia
Disturbed Thought Processes related to psychosis
Risk for Suicide related to depression or bipolar disorder
Ineffective Coping related to genetic diagnosis and family burden
Knowledge Deficit regarding genetic risk and mental illness

📌 Key Facts for Practice & Education:

Mental illnesses often have multifactorial inheritance (genes + environment)
Twin and family studies show strong heritability (e.g., ~80% for schizophrenia, bipolar disorder)
Some mental illnesses are part of genetic syndromes (e.g., Fragile X, 22q deletion)
Early recognition, family support, and multidisciplinary care improve outcomes

Published March 29, 2025By mynursingapp

Categorized as BSC SEM 4 PATHOLOGY 2 & GENETICS, Uncategorised

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