Unit III

1. Unit III Genetic/Developmental, Childhood, and Mental Health Diseases and Disorders

2. Chapter 19 Genetic and Developmental Diseases and Disorders

3. Anatomy and Physiology Cell nucleus 46 chromosomes – 23 pairs Somatic cells reproduce through mitosis Double then divide Germ cells (sex cells) reproduce through meiosis Haploid cells carrying 23 chromosomes

4. Anatomy and Physiology Normal females Sex chromosome is XX Normal male Sex chromosomes is XY Male sperm can be X or Y – male determines sex of child Chromosomes can be visualized by karyotyping Sex chromosomes can be evaluated by buccal smear

5. Anatomy and Physiology Female X germ cell is much larger than male Y cell and carries more genetic information Chromosomes are made of deoxyribonucleic acid (DNA) and in a specific order; each is called a gene Chromosomes (one from each parent) pair up during fertilization; these paired genes are alleles

6. Anatomy and Physiology Each gene in an allele can be dominant or recessive Homozygous – matched alleles such as BB or bb Heterozygous – unmatched alleles such as Bb Expression of a physical trait is called phenotype

7. Anatomy and Physiology Abnormalities can be due to: Chromosomal disorder Genetic disorder Environmental factors Combination of above Individuals acquire abnormal genes in two ways: Mutation of gene during meiosis Passage of abnormal gene from parents (heredity)

8. Anatomy and Physiology Genetic disorders are passed to offspring in four ways: Autosomal dominant Autosomal recessive Sex-linked dominant Sex-linked recessive

9. Anatomy and Physiology Approximately 2% of newborns are born with congenital anomalies Causes: 60% unknown cause 20% genetic 10% chromosomal 10% environmental

10. Diagnostic Tests Fetal ultrasound Detects malformations Amniotic fluid Reveals genetic and chromosomal disorders Maternal blood Reveals abnormal fetal substances

11. Musculoskeletal Muscular dystrophy (MD) Genetic degeneration or weakening of muscles Duchenne’s MD Most common type Cause: Sex-linked disorder passes mother to son Symptoms: Onset between 2 and 5 years of age Waddling gait, toe walking, lordosis, Gower’s maneuver Treatment: No cure Physical therapy, orthopedic devices, exercise helpful

12. Musculoskeletal Congenital hip dislocation (CHD) Abnormal hip joint resulting in femoral head slipping out of normal position Cause: Improper positioning in uterus, maternal hormones Symptoms: Asymmetrical folds of affected thigh Difference in leg length Limited abduction – Ortolanti’s sign Treatment: Closed or surgical reduction of femoral head

13. Musculoskeletal Clubfoot Also known as talipes equinovarus Common congenital abnormality of foot Cause: Unknown Symptoms: Foot or feet turn inward with toes pointed downward and heel drawn upward Treatment: Gradual straightening Cast Splints

14. Musculoskeletal Osteogenesis imperfecta Abnormally brittle bones leading to fractures Cause: Inherited gene mutation Symptoms: Frequent bone fractures Blue coloration of sclera of eyes Treatment: No cure Tendency for bones to fracture often disappears by adulthood

15. Neurologic Hydrocephalus Abnormal accumulation of cerebrospinal fluid in brain due to obstruction Cause: Congenital defect, infection, tumor Symptoms: Rapid enlargement of infant head and bulging eyes Tight scalp and prominent head veins Shrill, high-pitched cry Treatment: Surgical correction with shunt placement

16. Neurologic Cerebral palsy Congenital bilateral paralysis Cause: Inadequate blood or oxygen supply to brain during fetal development, birthing process, or infancy Symptoms: Hyperactive reflexes and rapid muscle contraction Muscle weakness with scissors gait

17. Neurologic Cerebral palsy Treatment: Physical and speech therapy Orthopedic cast, braces, and surgery Anticonvulsants Muscle relaxants No cure

18. Neurologic Spina bifida Congenital disorder Opening in spinal column Cause: Unknown Risk factors include maternal radiation, virus, genetic factors Symptoms: Differ with form of disease Forms of spina bifida Spina bifida occulta Meningocele Myelomeningocele Treatment: Surgery

19. Neurologic Huntington’s disease Genetic defect of chromosome 4 Cause: Genetic – if one parent has disorder, 50% chance in offspring Symptoms: Behavioral changes Unsteady gait Increasing dementia Treatment: No cure Medications reduce symptoms

20. Cardiovascular Congenital heart defects Heart and related vessels are most common sites of congenital defects Defects can range from small to quite large Collectively, these malformations are called congenital heart defects

21. Cardiovascular Congenital heart defects (continued) Cause: Unknown, but genetic tendency is strongly suspected Symptoms: Vary from mild (asymptomatic) to extreme with cyanosis, breathing difficulty, and heart murmurs Diagnosis: Electrocardiogram Physical examination Treatment: Early diagnosis Surgery to correct the defect

22. Cardiovascular Congenital heart defects (continued) Atrial septal defect Opening between right and left atria Commonly due to foramen ovale not closing at birth Causes increased workload on right heart Ventricular septal defect Most common heart defect Hole between right and left ventricle Blood shunted from left to right Causes increased workload on right heart

23. Cardiovascular Congenital heart defects (continued) Patent ductus arteriosus Connection between pulmonary artery and aorta that does not close off after birth Blood shunts from aorta to pulmonary artery Causes increased workload on heart and pulmonary system Coarctation of aorta Stricture or narrowing of aorta Causes increased blood pressure proximal to narrowing Causes increased workload on heart

24. Cardiovascular Congenital heart defects (continued) Tetralogy of Fallot One of the most serious of congenital defects Combination of four problems Pulmonary valve stenosis Right ventricle hypertrophy Ventricle septal defect Abnormal placement of aorta

25. Blood Sickle cell anemia (discussed in detail in Chapter 7) Chronic hereditary form of anemia Predominantly affects black population Hemophilia (discussed in detail in Chapter 7) X-linked hereditary disorder passed from mother to son

26. Digestive Digestive disorders both genetic and developmental range from mild to severe Many are diagnosed at birth Some are incompatible with life and must be corrected immediately

27. Digestive Developmental malformations Several developmental malformations occur in the digestive system Cause: Unknown Might be related to genetic tendencies Might be related to maternal risk factors Maternal rubella Poor maternal nutrition Smoking Alcoholism

28. Digestive Developmental malformations (continued) Meckel’s diverticulum Outpouching of diverticulum of the ileum Esophageal atresia Abnormal esophagus Congenital diaphragmatic hernia A hole in the diaphragm

29. Digestive Developmental malformations (continued) Imperforate anus Failure of the anus to connect to the rectum Cleft lip One or more splits in upper lip Affects boys more frequently than girls Treatment: Surgical repair

30. Digestive Developmental malformations (continued) Cleft palate More serious than cleft lip Involves roof of mouth Treatment: Surgical repair

31. Cleft Lip and Palate Photo courtesy Dr. Joseph Konzelman, School of Dentistry, Medical College of Georgia

32. Cleft Lip and Palate Photo courtesy Dr. Joseph Konzelman, School of Dentistry, Medical College of Georgia

33. Digestive Genetic digestive disorders Pyloric stenosis Narrowing of lower end of stomach Common anomaly of digestive tract Symptoms: Projectile vomiting Treatment: Pylorotomy

34. Pyloric Stenosis

35. Digestive Genetic digestive disorders (continued) Hirschsprung’s disease Absence of nerves in segment of colon Usually sigmoid colon Symptoms: Chronic constipation Abdominal distention Treatment: Surgical removal of affected segment Temporary colostomy may be necessary to allow adequate healing of colon

36. Digestive Genetic digestive disorders (continued) Phenylketonuria (PKU) Genetic disorder involving faulty metabolism of protein phenylalanine Diagnosis by blood test 72 hours after birth Mandatory in United States Lack of treatment can result in mental disability

37. Urinary Hypospadias Abnormal congenital opening of male urinary meatus on under surface of penis Chordee Abnormal fibrous band of tissue Epispadias Abnormal congenital opening of male urinary meatus on upper surface of penis Cause of these conditions: Unknown Treatments: No treatment to surgical repair

38. Urinary Wilms’ tumor Most common solid tumor affecting children and infants Cause: Thought to be genetic Highly malignant Usually replaces one whole kidney Symptoms: Asymptomatic until large enough to feel in child’s stomach Treatment: Chemotherapy Surgery

39. Reproductive Cryptorchidism Condition of undescended testes (discussed in Chapter 17) Turner’s syndrome Affects females; ovaries are abnormal or absent Cause: Chromosomal disorder Females have only one X chromosome Rather than two XX chromosomes Symptoms: Failure to develop normal secondary sex characteristics Treatment: Reduce growth with hormones and estrogen therapy

40. Reproductive Klinefelter’s syndrome Affects males; do not develop secondary sex characteristics Cause: Chromosomal disorder Affected males have extra X chromosome Symptoms: Not diagnosed until puberty due to abnormal male sexual development Sterility, abnormally small penis and testes General appearance of a eunuch – tall, slender body and long legs Treatment: Testosterone treatment and psychological counseling

41. Other Developmental Disorders Autism Developmental disorder characterized by difficulty communicating and in forming relationships Cause: Unknown Symptoms: Blank facial expression Involved with self – inaccessible to others Treatment Behavioral therapy Depends on severity and symptoms present

42. Other Developmental Disorders Stuttering Also known as stammering Developmental speech disorder Cause: Often occurs when child addresses an impatient or angry parent Symptoms: Hesitancy of starting and finishing words Prolonged pauses between words Treatment: Behavior modification Positive reinforcement

43. Multisystem Diseases and Disorders Cystic fibrosis Hereditary disorder that affect all exocrine glands Cause: Hereditary recessive disorder Symptoms: Affects all exocrine glands leading to viscous secretions Treatment: Postural drainage Chest-clapping Antibiotics Bronchodilators Expectorants Oxygen

44. Multisystem Diseases and Disorders Down syndrome Also called trisomy 21 – a condition of having 3 chromosomes instead of the normal 2 in the 21st position of the chromosome chain Symptoms: Mild to severe mental disability Flat nasal bridge Low-set ears Slanted eyes Epicanthus Thick, protruding tongue Abnormal extremities Organ defects Treatment: Highly individualized to maximize mental and physical abilities

45. Trauma Failure to thrive Lack of physical growth and development in infant or child Cause: Disturbance in mother–child relationship or failure to bond Symptoms: Weight loss or failure to gain weight Anorexia, vomiting, diarrhea Irritability Rag-doll limpness

46. Trauma Failure to thrive (continued) Symptoms: Unresponsiveness to affection Avoidance of eye contact Stiffening when cuddled Treatment: Teaching of mothering and nurturing behaviors to mother/parents Promotion of self-esteem

47. Trauma Fetal alcohol syndrome A group of symptoms and birth defects in an infant born to a mother who consumed alcohol during pregnancy Symptoms: Varying degrees of mental disability Decreased physical development Irritability in infants Hyperactivity in older children Microcephaly Increased incidence of ventricular septal defects

48. Trauma Congenital rubella syndrome Transmission of rubella virus to unborn fetus Can cause spontaneous abortion or major birth defects The most common defects are: Microcephaly Learning disorders Deafness Abnormal growth Heart defects Ocular lesions Prevention: Immunization No pregnancy for 3 months after immunization

49. Rare Diseases Anencephaly Absence of brain or cranial vault Not compatible with life Achondroplasia Decreased long bone growth leading to type of dwarfism Tay-Sachs disease Genetic error in lipid metabolism resulting in accumulation of toxins in brain