Aim: What are Genetic Conditions/diseases?

List at least 3 genetic conditions you know of.Why do you think they are genetic conditions?

What are genetic Diseases?A genetic disease is any

disease that is caused by an abnormality in an individual's genome.

Can range from small mutations in a single base to huge chromosome abnormality such as extra or missing chromosomes

Some are inherited others are caused by acquired mutations

Categorizing Genetic ConditionsIf we categorize genetic conditions by the way they are inherited there are 5 main types:Autosomal DominantAutosomal RecessiveSex-LinkedCodominant Mitochondrial

Autosomal dominantOne mutated copy of

the gene is enough for a person to be affected by an autosomal dominant disorder.

Autosomal dominant disorders tend to occur in every generation of an affected family.

Example: Huntington disease

Autosomal recessiveTwo mutated copies of

the gene are present in a person has an autosomal recessive disorder.

An affected person usually has unaffected parents who each carry a single copy of the mutated gene

Typically not seen in every generation of an affected family.

Example: Sickle cell Disease

Sex-linkedIncludes X-

linked dominant and recessive conditions

Affected gene is on sex chromosome.

Usually affects one gender more than the other

Example: Color Blindness

CodominantTwo different versions

(alleles) of a gene can be expressed, and each version makes a slightly different protein.

Both alleles influence the genetic trait or determine the characteristics of the genetic condition

Example: ABO blood group, alpha-1 antitrypsin deficiency

MitochondrialAlso known as maternal

inheritance.Applies to genes in

mitochondrial DNA. Only females can pass

on mitochondrial mutations to their children

Can show up in every generation of a family

Affect both males and females

Identify the following diseases by how they are inherited.

Just write down the number of the condition and the type of condition

1. Tay-Sachs Disease (chromosome 15)Progressive nervous system degeneration.A child is deaf and blind by one or two years-

progressive mental retardation, loss of muscular control; usually die at age three or four.

Most carriers choose to avoid the birth of a child because there is no treatment.

Both Parents need to pass on the gene for the child to have the condition.

2. Amyotrophic lateral sclerosis (ALS, Lou Gehrig=s disease) (chromosome 21)Affects 1 in 100,000 people worldwide, but only 10% of the cases are inherited. The other 90% are probably environmentally induced (don=t know cause).Fatal degenerative nerve disease.Stiffening and weakening of the legs and

arms, become quadriplegic, die as respiratory muscles become paralyzed.

One copy of the gene is enough to have the condition

3. Androgenic alopecia(AKA) Male Pattern BaldnessClassic androgenic hair loss in males begins

above the temples and vertex of the scalp. As it progresses, a rim of hair at the sides and rear of the head remains. 

The gene responsible is on the X chromosome

Affects males more than Females because Females need 2 copies of the gene to show symptoms'

4. Leber hereditary optic neuropathy?Although this condition usually begins in a

person's teens or twenties, rare cases may appear in early childhood or later in adulthood.

Can only be passed down by mothersGene responsible is found in the

mitochondria

5. Alpha-1 antitrypsin deficiency?Alpha-1 antitrypsin deficiency is an inherited

disorder that may cause lung disease and liver disease.

About 10 percent of infants with alpha-1 antitrypsin deficiency develop liver disease, which often causes yellowing of the skin and whites of the eyes (jaundice).

Two different versions of the gene may be active (expressed), and both versions contribute to the genetic trait.

Answers 1. Autosomal Recessive2. Autosomal Dominant3. Sex Linked4. Maternal or Mitochondrial5. Codominant