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.

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

9. 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.

11. 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).

12. • 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

13. 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

14. 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.

15. 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.

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

17. 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

18. 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.

19. 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.

20. 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.

21. 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.

23. 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.

24. 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.

25. Huntington’s Disease (HD)

26. Huntington’s Disease (HD)

27. Huntington’s Disease (HD)

28. 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

29. • 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

30. Down Syndrome

31. 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

32. Duchenne Muscular Dystrophy

33. Duchenne Muscular Dystrophy

34. 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.

35. 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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