Genetic Disorders

What are genetic disorders?

• You are born with them – they are inherited.• Some are common, others are very rare• Examples:– World’s tallest man: Robert Wadlow (8 foot, 11.1

inches tall, overactive pituitary gland)– “Tree man”: Dede Koswara (Epidermodysplasia

Verruciformis, form of HPV)– Elephant Man: Joseph Carey Merrick

World’s Tallest Man

• Robert Wadlow (8 foot, 11.1 inches tall)

Robert and his father

“Tree Man”

• Dede Koswara (Epidermodysplasia Verruciformis, form of HPV)

When 10 years old, and out playing in the forest, he cut his knee… warts appeared and continued to grow. These warts smelled and eventually became extreme. He lost his family and his job.

His GENETIC condition is a rare immune deficiency syndrome, similar to AIDS, where his body’s immune system is very weak, which allowed the virus (warts) to grow out of control.

Elephant Man

• Joseph Carey Merrick (Proteus Syndrome)

Starting at the age of 2, strange tumors began to grow all over his body.

Definitions• Disease– Impairment of the normal state of living, often in

response to environmental factors or infective agents.• Malnutrition, industrial hazards, climate• Worms, bacteria, viruses

• Disorder– Disturbance in, or abnormal, physical or mental

condition• Syndrome– Group of symptoms that together are characteristic

of a specific disease or disorder.

7

HeredityKaryotypeA picture of the

chromosomes from a human cell arranged in pairs by size and banding pattern

First 22 pairs are called autosomes

Last pair are the sex chromosomes

XX female or XY male

How do you do a Karyotype?

• Cells that are dividing are collected – – Amniocentesis• Needle inserted into the uterus to collect

fluid and fetal skin cells

• Sample is shipped off to a Cytogenetics Lab– At the lab, the chromosomes in the

nucleus of the cells are isolated, dyed (so they can be seen), then a picture is taken.

– Cells are then counted, sorted and another picture is taken.

LabYou are going to make your own karyotype from

cells taken from a human with a genetic disorder.

First, Cut out the template that has one of the chromosome pairs already in size order and glue into your notebook.

Then, match up the chromosomes based on size and banding pattern and glue them to the template.

You will have an extra chromosome – find where it goes and glue it in.

Then begin answering the questions in your lab.

Karyotype Notation

• In one line, you will know everything you need to know about the karyotype.

• Contains – Number of chromosomes in Karyotype– Sex chromosomes–Where extra (+) or missing (-)

chromosomes are

Karyotype Notation

• Normal46, XX• Female

46, XY• Male

• Abnormal• 45, XY, -8• Missing 1

chromosomes, Male, at #8

• 47, XY, +18• Extra Chromosome,

Male, at #18

Presentations

• Be Respectful to your fellow peers– Listen to those who are presenting– Pay attention to the presenter– When presenting, be loud enough for all to hear– Be proud of your work

Down Syndrome• Trisomy 21 (Full: All cells)• Physical symptoms: Flat face, upward slanted eyes,

short neck, small hands/feet.• Other symptoms: Hearing problems, intestinal

problems, heart disease, skeletal problems, eye problems.

• Not inherited – typically happens when an older woman has a child. Chromosomes don’t separate and the child gets an extra one.

• High risk: 1 in 100 women (age 40+) have a child with Down Syndrome

Patau Syndrome• Trisomy 13 (Full: all cells involved, Mosaic: Some cells have

extra copies, Translocation: rearrangement of genetic material between chromosome 13 and another)

• Physical symptoms: Cleft lip or palate, polydactyl, hernias, small eyes, small head,

• Other symptoms: Mental retardation, seizures, heart disease and/or failure, deafness, vision problems.

• Typically not inherited – typically happens when chromosomes don’t separate during the formation of eggs and sperm (Called Non-disjunction). Translocation may be inherited.

• Rare: 1 in 16,000 newborns. *More than 80% die in the first year after birth.

Kleinfelter’s Syndrome• XXY Condition (Full: all cells or Mosaic: some

cells.)• Physical symptoms: Weak muscles, less facial hair,

larger breasts, tooth decay.• Other symptoms: Reduced strength, language

delay, quiet and shy, infertile, intellectual problems.

• Not inherited – typically happens when chromosomes don’t separate during the formation of eggs and sperm.

• High risk: 1 in 500

Hermaphrodite

• Organism that is fully male and fully female.– Snails and slugs

• Intersex (preferred term for humans)– Have both testicular and ovarian tissues (not fully both)– 1 out of 2,000 children born– 46, XX Ovaries inside, but have a “penis-like” external

genitalia– 46, XY Testes normal, malformed or absent, and genitalia

normal, malformed or female in nature.– 47, XXY or 47, XXX or 45, X0 Typical genitalia, no mixtures

Spina Bifida

• Myelomeninocele, Spina bifida occulta– Most common forms

• Happens in 1 out of 800 births• What is it?– Birth defect– Backbone/spine don’t close before birth– Many times, there is a sac sticking out of the back.

• Normally, in the 1st month of pregnancy, the two sides of the backbone join together to cover the spinal cord, nerves and meninges.

Spina Bifida Babies• Must handle carefully!• Need surgery to repair spine.• Typically present:– Hydrocephalus– Hip dislocation– Weakness or paralysis of hips/legs/feet– Lack of sensation– Abnormal feet/legs– Bladder problems

Spina Bifida Children and Adults

• Length of life typically not effected.• Many wear braces, corrective shoes, and/or are confined to a wheelchair.• Get many UTI’s• Hydrocephalus

Causes of Spina Bifida

• Don’t really know – • Could be low folic acid• Could be a virus• Could be inherited

Autism• What is it?– Neurodevelopment disorder• Problems with social interactions and communication

– Unresponsive– Withdrawn– Avoid eye contact– Can’t empathize (don’t understand feelings/expressions)

• Repetitive behaviors, or an avoidance of behaviors– Rocking, spitting, mumbling– Avoidance of water, rooms, colors

• Food textures• Don’t do well with change – need structure

What causes Autism?

• Thought to be genes AND environment.– DNA – hereditary– Chemicals in the brain• Natural interactions• Foods eaten• Environmental factors

How is Autism treated?

• There is no cure• Educational interventions– Extra help in learning modalities and techniques

• Behavioral interventions– Training to develop social and language skills

• Dietary interventions– Alteration of food to accommodate needs

• Medications

Goldenhar Syndrome• Congenital

– Means: appears at birth• Ranges in severity, typically unilateral

– Means: affects one side• Abnormalities typically involve:

– bones of the face (cheekbones and jaw), – bones of the spine (minor to severe scoliosis)– eyes (up to blindness)– Ears (up to deafness)– Heart– Lungs– Kidneys– Skin tags or pits

Goldenhar Syndrome

What is it like?

• How do you feed a child with a cleft palate?– http://www.cleftline.org/parents/feeding_your_b

aby (Getting Started)

• How do you communicate?– Verbally and non-verbally – ASL

• How do you cope?– You learn, you educate, and you take things one

day at a time.

Jeremy Dale’s Story

Jeremy Dale• Taken from: http://www.cleftline.org/story_of_the_month/feb04

written by George and Kristine Dale

• “Our son, Jeremy, was born on September 12, 1999. Like typical parents, we were very excited about the birth of our first child and were confident that the most perfect little baby would be coming soon. Our perfect little baby did arrive — 7 weeks early and, a shock to us, was born with a severe facial abnormality. Jeremy was 3 lbs/10 oz and 16 ½” long and was diagnosed with Goldenhar syndrome. For Jeremy, Goldenhar syndrome meant a large left facial cleft, extreme cleft palate, the absence of his left ear, an underdeveloped left eye and 2 hemi-vertebrae located in the middle of his spine and at the top of his spine causing congenital scoliosis. Jeremy was immediately admitted to the NICU and stayed there for almost 6 weeks.”

Jeremy Dale

• 1st facial surgery February 2000• 2nd facial surgery 2 weeks later – February 2000• 3rd facial surgery – March 2000 (after he reached 20 pounds

– to repair palate)• October 2001 – spine surgery (then body cast for 4 months

because of scoliosis)• Total of 9 surgeries in the first 4 years with many more to

come.• Other than all the medical needs, he is a typical child –

loves to play music, watch TV, etc. He communicates by sign language because he can not speak.

Jeremy Dale’s Story Continued

• “We’ve all had our struggles with stares and comments from people who don’t understand, but we handle each one as it comes. We try to explain Jeremy’s condition and educate as many people as we can. To those who know and love Jeremy, he is still that ‘perfect’ little baby boy who was born 4 years ago.”