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 –

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

Famous people who had it… Woody Guthrie

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