Genetic disorders

Genetic disaese among children

1. GENETIC DISORDERS Prepared by Raveen Isamel Abdullah B.CS.in Nursing Hawler medical university College of nursing 2016-2017

2. OUTLINES Genetic disorders Heredity of genetic disorders Gene mutation and types of mutation Diagnosing genetic disorders Purpose of diagnosing Prognosis Treatment Huntington’s Disease (HD) Down Syndrome Duchenne Muscular Dystrophy

3. OBJECTIVES By end of seminar audiences will understand : Genetic disorders in general The heredity of genetic disorders The causes of occurring genetic disorders. the most common strategies of diagnosing the gene disorder

4. Genetic disorders A genetic disease occurs when a person has one or more abnormal genes, missing genes, extra genes, inactivated genes, or overly active genes that lead to a medical condition .

5. Understanding Genetic Disorders Genes are the building blocks of heredity. They are passed from parent to child. Genes are found within the cells of all organisms. An individual's genes are present in a large molecule called deoxyribonucleic acid (DNA). They hold DNA , the instructions for making proteins . DNA is made up of different combinations of four nucleic acids (adenine, thymine, cytosine, guanine), which are arranged in different lengths. Proteins do most of the work in cells. Proteins move molecules from one place to another, build structures, break down toxins, and do many other maintenance jobs.

6. Human cells normally contain 23 pairs of chromosomes. One chromosome in each pair comes from father, the other from mother.

7. Understanding genetic disorders Cont Sometimes there is a mutation , a change in a gene or genes. The mutation changes the gene's instructions for making a protein, so the protein does not work properly or is missing entirely. This can cause a medical condition called a genetic disorder. person can inherit a gene mutation from one or both parents .

8. Heredity Of Genetic Disorders A person's DNA is contained inside two sets of chromosomes. Each parent provides one set of 23 chromosomes to his or her offspring. Therefore, each person has 23 pairs of chromosomes. The X and Y chromosomes are called the sex chromosomes because they distinguish males from females. Females have a pair of X chromosomes, while males have one X and one Y chromosome. Certain genetic diseases occur when there are genetic mutations in sex chromosomes, and these can affect males and females differently. To inherit an autosomal recessive trait, a person must inherit two copies of a mutated gene (one from each parent).

9. Individuals who inherit only one copy of the mutated gene do not generally experience disease symptoms but are called "carriers" because they can still pass the trait on to their children. Genetic conditions are usually inherited, meaning that they are passed down from parents to their children. However, some genetic disorders occur in individuals with no family history of the disorder and are instead caused by genetic mutations that occur during the development of the egg, sperm, or embryo. Heredity Of Genetic Disorders

10. Gene Mutation and Types A gene mutation is a permanent alteration in the DNA sequence that makes up a gene. Types: Acquired Mutations Hereditary Mutations

11. Heredity mutation Hereditary mutations are inherited from a parent and are present throughout a person’s life in virtually every cell in the body. These mutations are also called germ line mutations because they are present in the parent’s egg or sperm cells, which are also called germ cells. When an egg and a sperm cell unite, the resulting fertilized egg cell receives DNA from both parents. If this DNA has a mutation, the child that grows from the fertilized egg will have the mutation in each of his or her cells.

12. Acquired mutation Acquired mutations occur at some time during a person’s life and are present only in certain cells, not in every cell in the body. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if a mistake is made as DNA copies itself during cell division. Acquired mutations in somatic cells (cells other than sperm and egg cells) cannot be passed on to the next generation.

13. Types Of Genetic Disorders Single-gene disorders, where a mutation affects one gene. Sickle cell anemia is an example. Chromosomal disorders, where chromosomes (or parts of chromosomes) are missing or changed. Chromosomes are the structures that hold our genes. Down syndrome is a chromosomal disorder. Complex disorders, where there are mutations in two or more genes. Often lifestyle and environment also play a role. Colon cancer is an example.

14. Diagnosing Genetic Disorders Genetic tests are tests on blood and other tissue to find genetic disorders Purpose of genetic tests Finding genetic diseases in unborn babies Finding out if people carry a gene for a disease and might pass it on to their children Screening embryos for disease Testing for genetic diseases in adults before they cause symptoms Making a diagnosis in a person who has disease symptoms Figuring out the type or dose of a medicine that is best for a certain person

15. Physical Examination Certain physical characteristics, such as distinctive facial features, can suggest the diagnosis of a genetic disorder. A geneticist will do a thorough physical examination that may include measurements such as the distance around the head (head circumference), the distance between the eyes, and the length of the arms and legs . Depending on the situation, specialized examinations such as nervous system (neurological) or eye (ophthalmologic) exams may be performed. The doctor may also use imaging studies including x-rays, computerized tomography (CT) scans, or magnetic resonance imaging (MRI) to see structures inside the body .

16. Personal Medical History Information about an individual's health, often going back to birth, can provide clues to a genetic diagnosis. A personal medical history includes past health issues, hospitalizations and surgeries, allergies, medications, and the results of any medical or genetic testing that has already been done.

17. Family Medical History Because genetic conditions often run in families, information about the health of family members can be a critical tool for diagnosing these disorders. A doctor or genetic counselor will ask about health conditions in an individual's parents, siblings, children, and possibly more distant relatives. This information can give clues about the diagnosis and inheritance pattern of a genetic condition in a family.

18. Laboratory Tests Genetic testing: Molecular, chromosomal, and biochemical genetic testing are used to diagnose genetic disorders. Other laboratory tests that measure the levels of certain substances in blood and urine can also help suggest a diagnosis.

19. Prenatal Diagnosis Prenatal diagnosis can detect the presence of characteristic abnormalities in fetal development through ultrasound, or detect the presence of characteristic substances via invasive procedures which involve inserting probes or needles into the uterus such as in amniocentesis.

20. Huntington’s Disease (HD) Huntington’s Disease (HD) causes the degeneration of the nerve cells in the brain and central nervous system.  This hereditary condition is autosomal dominant disorder , meaning that children have a 50-percent chance of developing it and passing it along to their own children if one of their own parents has it . Treatment aims to limit the course of the disease. HD typically shows itself when the individual is between 30 and 40-years old—however, rare forms begin in childhood. Symptoms of HD include uncontrolled movement (chorea), difficulty swallowing, behavioral changes, difficulty balancing and walking, memory, speech, and cognitive loss.

21. Huntington’s Disease (HD)

22. Huntington’s Disease (HD)

23. Huntington’s Disease (HD)

24. Down Syndrome Down Syndrome, a common chromosomal abnormality that effects approximately 1 in 1000 newborns (particularly in older expectant mothers), results when an extra copy of genes occurs on chromosome 21 . Although Downs can be detected by pre-natal testing,  babies affected typically show the following features at birth—decreased muscle tone in the face, developmental delays, and heart and digestive system defects

25. Trisomy 21. the child has three copies of chromosome 21 (instead of the usual two copies) in all cells. This is caused by abnormal cell division during the development of the sperm cell or the egg cell. Mosaic Down syndrome. In this rare form of Down syndrome, children have some cells with an extra copy of chromosome 21. This mosaic of normal and abnormal cells is caused by abnormal cell division after fertilization. Translocation Down syndrome. Down syndrome can also occur when part of chromosome 21 becomes attached ( translocated ) onto another chromosome, before or at conception. These children have the usual two copies of chromosome 21, but they also have additional material from chromosome 21 attached to the translocated chromosome. Down Syndrome Etiology

26. Down Syndrome

27. Duchenne Muscular Dystrophy Symptoms of Duchenne Muscular Dystrophy typically show themselves before the age of 6. The condition causes fatigue and weakness of the muscles, which starts in the legs and then gradually progresses to the upper body, leaving individuals wheelchair bound by the age of 12-years-old . For some reason the condition affects mostly boys with symptoms such as heart and respiratory difficulties, deformity of the chest and back, and potential mental retardation

28. Duchenne Muscular Dystrophy

29. Duchenne Muscular Dystrophy

30. Treatment Most treatment options revolve around treating the symptoms of the disorders in an attempt to improve patient quality of life. Gene therapy refers to a form of treatment where a healthy gene is introduced to a patient. This should alleviate the defect caused by a faulty gene or slow the progression of disease. A major obstacle has been the delivery of genes to the appropriate cell, tissue, and organ affected by the disorder.

31. Prognosis Not all genetic disorders directly result in death, however there are no known cures for genetic disorders. Many genetic disorders affect stages of development such as Down syndrome. While others result in purely physical symptoms such as Muscular Dystrophy. Other disorders, such as Huntington's Disease show no signs until adulthood.

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