Genetic Disorders and Counseling

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Genetic Disorders and Counseling

• By Courtney Coyle, Mary Neville, and Ethan
  Linville
• Mr. Taylors 8th Grade Gifted Science Class
• April 2005

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Down Syndrome

• Down Syndrome is a genetic disorder caused by
  extra genetic material. It affects over 350,000
  people in the United States alone and is the most
  common imbalance in the number of autosomes in
  people.

Source
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Causes of Down Syndrome

• Down syndrome is the most common form of mental
  retardation caused by chromosomal aberration. The
  disease results from having three copies of all
  or a portion of chromosome 21. The risk of having
  a liveborn with Down syndrome increases with the
  mother's age, from 1 in 1000 at age 30 to 9 in
  1000 at age 40. Most cases (95) of Down
  syndrome result from the presence of an intact
  extra copy of chromosome 21 however,
  translocation of a 1 copy of a critical region of
  this chromosome to another acrocentric chromosome
  (most often chromosome 14) can also lead to Down
  syndrome.

Source

movie
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Diagnosis Pre-natal

• Two types of procedures are available to pregnant
  women screening tests and diagnostic tests. The
  screening tests estimate the risk of the baby
  having Down syndrome. Diagnostic tests tell
  whether or not the baby actually has Down
  syndrome.

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Symptoms

• Decreased muscle tone at birth
• Separated sutures (joints between the bones of
  the skull)
• Asymmetrical or odd-shaped skull
• Round head with flat area at the back of the head
• Small skull
• Upward slanting eyes, unusual for ethnic group
• Small mouth with protruding tongue
• Broad short hands
• Single crease on the palm
• Retarded growth and development
• Delayed mental and social skills (mental
  retardation)
• Iris lesion (an abnormality of the colored part
  of the eye called Brush field spots)

Source
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Effects of Down Syndrome

• Many children with Down syndrome have health
  complications beyond the usual childhood
  illnesses. Approximately 40 of the children have
  congenital heart defects. It is very important
  that an echocardiogram be performed on all
  newborns with Down syndrome in order to identify
  any serious cardiac problems that might be
  present. Some of the heart conditions require
  surgery while others only require careful
  monitoring. Children with Down syndrome have a
  higher incidence of infection, respiratory,
  vision and hearing problems as well as thyroid
  and other medical conditions. However, with
  appropriate medical care most children and adults
  with Down syndrome can lead healthy lives. The
  average life expectancy of individuals with Down
  syndrome is 55 years, with many living into their
  sixties and seventies.

Source
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How it Affects Everyday Life

• Most children with Down syndrome have mild to
  moderate impairments but it is important to note
  that they are more like other children than they
  are different. Early Intervention services should
  be provided shortly after birth. These services
  should include physical, speech, and
  developmental therapies. Most children attend
  their neighborhood schools, some in regular
  classes and others in special education classes.
  Some children have more significant needs and
  require a more specialized program.

Source
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Treatments

• There is no specific treatment for Down syndrome.
  Special education and training is offered in most
  communities for mentally handicapped children.
  Specific heart defects may require surgical
  correction. The potential for visual problems,
  hearing loss, and increased susceptibility to
  infection will require screening and treatment at
  appropriate intervals.

Source
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Hemophilia

• Hemophilia is a rare genetic blood clotting
  disorder that primarily affects males. People
  living with hemophilia do not have enough of, or
  are missing, one of the blood clotting proteins
  naturally found in blood. Two of the most common
  forms of hemophilia are A and B. In persons with
  hemophilia A (also called classical hemophilia),
  clotting Factor VIII is not present in sufficient
  amounts or is absent. In persons with hemophilia
  B (also called Christmas disease), clotting
  Factor IX is not present in sufficient amounts or
  is absent. People with hemophilia do not bleed
  more profusely or bleed faster than normal they
  bleed for a longer period of time.

Source
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Types of Hemophilia

• hemophilia A - caused by a lack of the blood
  clotting factor VIII approximately 85 percent of
  hemophiliacs have type A disease.
• hemophilia B - caused by a deficiency of factor
  IX.
• von Willebrand disease - a part of the factor
  VIII molecule known as von Willebrand factor or
  ristocetin cofactor is reduced. The von
  Willebrand factor involves helping the platelets
  (blood cells that control bleeding) attach to the
  lining of a vein or artery. This missing factor
  results in prolonged bleeding time because the
  platelets are unable to attach to the wall of the
  vessel and form a plug to stop the bleeding.

Source
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Causes of Hemophilia
Source

• Hemophilia types A and B are inherited diseases
  passed on to children from a gene located on the
  X chromosome. Females have two X chromosomes,
  while males have one X and one Y chromosome. A
  female carrier of hemophilia has the hemophilia
  gene on one of her X chromosomes. When a
  hemophilia carrier female is pregnant, there is a
  50/50 chance that the hemophilia gene will be
  passed on. If the gene is passed on to a son, he
  will have the disease. If the gene is passed on
  to a daughter, she will be a carrier. If the
  father has hemophilia but the mother does not
  carry the hemophilia gene, then none of the sons
  will have hemophilia disease, but all of the
  daughters will be carriers.

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Effects of Hemophilia

• The most common cause of disability from
  hemophilia is chronic joint disease, or
  arthropathy, which is caused by uncontrolled
  bleeding into the joints.
• Hemorrhage, which is a severe internal or
  external discharge of blood, is a continuing
  problem

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Symptoms
normal

• Bruising
• Bleeds easily
• Bleeding into a joint
• Bleeding into the muscles
• Bleeding from injury or bleeding in the brain
• Other sources of bleeding

abnormal
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Long-term Effects

• Hemophilia is a lifelong disease. With the
  advances of specific clotting factors in
  laboratories, prevention and treatment of bleeds
  is improving.
• With careful management, informed decisions, and
  recognition of complications, many children with
  hemophilia can live relatively healthy lives with
  a normal lifespan.

Source
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Treatment

• Parents may want to purchase soft toys with
  rounded corners for young children. Padded
  clothing and helmets may be necessary for the
  child that is learning to walk or becoming more
  active. Contact sports in school should be
  evaluated for risks of injury to the child.
• Immunizations may need to be given under the skin
  instead of in the muscle to prevent deep muscle
  bleeds.
• Joint hemorrhages may require surgery and/or
  immobilization.
• Before surgery, including dental work, your
  child's physician may recommend factor
  replacement infusions to increase the child's
  clotting levels prior to the procedures.
• Your child's physician may also recommend the
  discontinuation of aspirin, and
  aspirin-containing products, since these products
  have been linked to bleeding problems.
• Blood transfusions may be necessary if
  significant blood loss has occurred.
• Proper dental hygiene is a preventive measure.

Source
Movie
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Genetic Counseling

• An educational counseling process for individuals
  and families who have a genetic disease or who
  are at risk for such a disease. Genetic
  counseling is designed to provide patients and
  their families with information about their
  condition and help them make informed decisions.

Source
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How Long Does Counseling Take?

• Some genetic counseling sessions are simple and
  require only one visit. Other times, multiple
  sessions are needed to collect additional
  information, to update the family or to deal with
  ongoing medical and/or psychosocial problems.

Source
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Pedigrees and Counseling

• An accurate pedigree is an important part of
  genetic counseling. A pedigree is used to help
  make a diagnosis of a genetic disease, to
  determine a person's risk of developing a genetic
  disease or to determine the risk of having a
  child with a genetic disease. At minimum, a
  pedigree includes first degree relatives (parents
  and siblings), second degree relatives (aunts and
  uncles) and third degree relatives (cousins and
  grandparents). The counselor may ask questions
  about more distant relatives like great-uncles or
  second cousins when necessary.

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What Happens During Counseling

• After medical tests are completed and records are
  collected, the genetic counselor may be able to
  make a diagnosis, or just as importantly,
  determine that a person does not have or is not
  at risk for a genetic disease. The pedigree can
  also be used to estimate the risk relatives face
  to develop a genetic disease or have a child with
  a genetic disease.

Genetic counselor examining human karyotype
Source
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Reactions to Counseling

• Patients can react in unexpected ways when they
  learn their genetic risk status. Some people take
  the information matter-of- factly. Others react
  with anger, shock, denial, grief, depression,
  confusion, and guilt. Treating and caring for
  people with genetic diseases can be expensive,
  yet some people may lose their jobs and health
  insurance because of their risk of developing a
  genetic disease. Someone diagnosed with a genetic
  disease may be avoided by other relatives because
  the relatives don't know what to say or because
  they don't want to face up to the possibility
  that they too may develop the same genetic
  disease. Other people may have a hard time
  understanding the meaning of risk - a risk of 10
  may seem high to one relative but seem low to
  another relative.

Source
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Ways to Cope with Disorders

• Genetic counselors try to help families cope with
  the many ramifications of genetic testing.
  Patients who are having severe psychosocial
  problems may be referred to psychiatrists, social
  workers, or counselors. Genetic counselors can
  also help families who are having problems with
  insurance companies or employers who may not
  understand the medical implications of genetic
  testing.

Source
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Sources

• Answers
• Genetic Disorder Corner
• National Human Genome Research Institute
• MadSci Network Genetics
• National Association for Down Syndrome
• Down syndrome (Disease) - Detroit, Michigan
• Hemophilia Galaxy
• MCG Health System
• Yale Medical Group
• Medicine Net
• The Natural Health Museum

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The End