Genetic Diseases

the genetic diseases for unit 8 in Biology

Autosomal dominant

Huntington’s Chorea, Marfan Syndrome, Achondroplasia

Autosomal Recessive

PKU, sickle cell anemia, Albinism, Tay-sachs, CF

Sex-linked Recessive

Hemophilia, Duchenne MD, Color blindness

Huntington’s Disease (HD)

• Neurons in the brain break down over time

• Most common in people of european descent - not common in Asians/Africans

• Symptoms:

  • Involuntary movement

  • Difficulty focusing/learning new info

  • Depression

  • Mood swings

  • Cognitive decline

• Fatal: symptoms cont to get worse after its onset and can cause death in 13-15 years

• Develops around 30s-50s

CF

• The body fails to move Cl through the cells due to a mutated gene

• Most common in white americans

• More men have it but women have it worse

• People can’t absorb fats, proteins, some vitamins and enzymes in pancreas are blocked by mucus

• Symptoms

  • Constance coughing w/ phlegm

  • Mucus buildup leading to lung infections - bronchitis and pneumonia

  • Sinus infections

  • Damaged digestive system - blocked pancreas

  • Diabetes

  • Delayed puberty

  • Diseases in the liver

  • Infertility

Sickle Cell Anemia

• Causes hemoglobin (protein that delivers oxygen to red blood cells) to be odd in shape

  • Abnormal shapes causes the cells to become hard and sticky → cells get stuck and block blood flow

• Most common in those of african descent. Also common of those from India, Mediterranea and Saudi arabia

• Symptoms:

  • Anemia

  • Panic crisis - episodes of extreme pain

  • Swelling of extremities (hands and feet)

  • Eye problems

  • Delayed growth

Tay-Sachs

• Fatal

• lack of gene coding for the enzyme hexosaminidase-A

  • An enzyme that destroys fat, used repeatedly in the development of the brain and nervous system

• The total lack of the gene that makes the enzyme causes the inability to destroy any fat build up

• Very rare put most common in Ashkenazi Jewish

• Symptoms:

  • Gradual, extensive damage to the brain and nervous system until death

  • Inability to destroy fat build up

PKU

• Trait that creates an error of metabolism due to a deficiency of an enzyme phenylalanine (PAH)

• Most common in turkey and ireland and those of american and european ancestry

• Occurs when an individual inherits 2 mutated PAH genes on chromosome 12

• Strict diets w/ certain supplements and no PAHs are necessary to help break down food properly

• Symptoms:

  • Organ damage

  • Unusual posture

  • Mental disorders

  • Problems in pregnancy

Marfan Syndrome

• Gene FBN1 attaches to chromosome 15

• Can cause:

  • Longer and thinner frame

  • Abnormally shaped chest and aorta (fragile)

  • Possibility of a curved spine

• Most commonly found in ages 15-19 - equally rare in males and females

Hemophilia

• Messes with blood clotting - excess internal/external bleeding can occur after specific triggers or spontaneously

• Mutation of the genes that code for coagulation factors

  • A - lack factor VIII

  • B - lack factor IX

• Effects:

  • Joint bleeding → disease and pain

  • head/brain bleeding → seizures and paralysis

  • non stop/bleeding of major organ → death

Color Blindness

• Groups of conditions that change the perception of a person’s ability to distinguish different colors of the spectrum

• There are 3 types of cones - red, green and blue - each containing photopigments that are sensitive to a specific wavelength of light

• When the cones are combined a person can see colors but irregularities will lead to color blindness

  • Not specifically hereditary - injury/illness

• Deuteranomaly - RG color blindness (most common)

• Protanopia - missing red-cone, only can see blue/green

• Tritanopia - blue-yellow, troubless seeing b/w colors contain B or Y

Duchenne MD

• Resulting from a mutation in the dystrophin gene

• Dystrophin protein is responsible in maintaining a large portion of the body’s muscle structure and function

• Occurs when not enough dystrophin is present in the body

• Likely to die around 20 yrs old

• symptoms/characteristics:

  • Respiratory muscle weakness/cardiomyopathy

  • Shorter stature

  • Lack of ambulation (ability to move/walk without help)

  • Sometimes learning disabilities

Albinism

• Condition that leads to someone having very light skin, hair and eyes and happens when someone has less melanin than usual in their body

• Most people with it are just as healthy as anyone else - normal life span

• Most common in the sub-saharan region of Africa

• The most common type is type 1 (x-linked) - ocular albinism

• Symptoms:

  • Pale skin

  • Very light hair

  • pink/light blue/green/gray/purple eye

  • Light sensitive eyes

  • Lazy eye

  • Back and forth movement of the eyes

  • Vision problems

  • Increased risk for skin cancer

Acondroplasia

• The limbs and skeletal structure of a developing fetus are shortened

• It's the most common type of dwarfism

• The chromosome associated with is it the short arm of chromosome 4 which codes for the gene FGFR3 which codes for growth factor

• Symptoms:

  • Abnormally shaped bones

  • Shorter height (42 - 56 inches)