interesting genetic disorders and diseases, and abnormalities
TRANSCRIPT
Interesting Genetic Disorders and Diseases, and Abnormalities
The difference between…
• Abnormality- rare or uncommon version of a trait
• Genetic disorder- inherited condition that sooner or later will result in medical problems which may be severe
• Syndrome- abnormality or disorder characterized by a specific set of symptoms
What’s wrong with this hand?
Polydactyly
• Sometimes abnormalities can be accurately predicted using a pedigree
• Polydactyly is defined by having an extra finger(s) or toe(s)
• Usually they are benign and sometimes removed soon after birth
• It is autosomal dominant
Animals with Polydactyly
Ellis-Van Creveld Syndrome
• Often a result of a “founder effect” and therefor found in many Amish communities– Founder Effect is a loss of genetic variation which occurs
when a new population is founded by a very small number of individuals; relatively low genetic variation
• Doesn’t mean it doesn’t occur in populations outside of the Amish community, but it has a particularly high rate in Amish, and is fairly rare outside of it
• Autosomal recessive
What is it?
• Genetic condition that affects bone growth• Symptoms include– Cleft palate or lip, extra fingers, short arms and
legs, short height, sparse absent or fine textured hair, peg or widely spaced teeth, teeth present at birth, heart defects, growth hormone deficiency,
Marfan Syndrome
• Hereditary condition affecting the body’s connective tissue, and also affects many other body systems,– Skeleton– Eyes– Heart and Blood Vessels– Skin– Lungs
What causes it?
• Mutations in gene for fibrillin– Fibrillin is a protein in connective tissue– Results in loosening of connective tissue
Who Gets it?
• It’s estimated that 1 in 5,000 people in the world have Marfan Syndrome
• It has been fund in both genders, and in all ethnicities
• Inherited from one or both parents, sometimes a child may have Marfan Syndrome even if both parents are unaffected
• If a parent has Marfan Syndrome a child has a 50% chance of having it as well, if neither parent a 1 in 10,000 chance
Diagnosis
• May not be diagnosed until later in life• Wide range of symptoms make it difficult to
diagnose• Some Symptoms are– Scoliosis, nearsightedness, retinal detachment,
cataracts, glaucoma, Heart murmurs, palpitations, Stretch marks, snoring, sleep apnea
Famous people who had it…
• Flo Hymen
• Michael Phelps– http://www.clevelandleader.com/node/6446#
Huntington’s Disease
• A neurodegenerative disorder, leads to cognitive decline and dementia– Cognitive is things like memory, decision making,
and problem solving• Symptoms begin to show up later in life
typically• Common in people of Western European
descent• Autosomal Dominant
Genetic testing contorversy
• An individual can be tested at any point in life for this disease, even before symptoms appear– which raises the questions: when is someone
mature enough to make that decision, should parents have their children tested
Symptoms
• Start out as unsteady gait, and general lack of coordination
• Progress to jerky body movements, decline of mental abilities, behavioral and psychiatric problems, compulsive behaviors
• No Cure
Tay-Sachs Disease
• A recessive genetic disorder• Fairly rare, and found commonly in Eastern
European Jewish populations, French Canadians in southeastern Quebec, and cajuns in southern Louisiana
Symptoms
• Generally within the first few months of life with a prognosis of only a few years– Infants appear to have normal development early in
life, and begin to have symptoms after about 6 months
– Sometimes TSD doesn’t present itself until a child is about 10 years old, they have speech, and swallowing difficulties, unsteady gait and spasticity
– Adult onset TSD is often misdiagnosed, same as Juvenile, plus psychiatric illnesses
Symptoms cont.
• All sufferers have a cherry red macula, observable by physicians using a ophthamolscope
• Infants become increasingly “floppy” have trouble sitting up, or rolling over