Question

part ii: what is a genetic disorder?
use information from the presentation to help you fill in the \description\ column of the chart.

type of genetic
disorder\tdescription\texample(s) – include informaiton
about the cause of the disease as well
as how the disease affects the patient.

single gene

• recessive
• dominant
• sex - linked\tcaused by variations or mutations in the dna sequence of a specific gene. dna affects\t

multifactorial\t\t

chromosomal\t\t

mitochondrial\t\t

research the following disorders and match them with the appropriate type of genetic disorder. record
information about each disease in the \example\ column of the chart.

• duchenne muscular dystrophy
• cystic fibrosis
• huntingtons disease
• down syndrome
• leber hereditary optic neuropathy
• alzheimer’s disease

Explanation:

To fill the chart, we analyze each genetic disorder type:

1. Single Gene Disorders (Recessive, Dominant, Sex - linked)

• Description: Caused by mutations in the DNA sequence of a single gene. In recessive disorders, two mutated alleles are needed (e.g., Cystic Fibrosis). Dominant disorders need only one mutated allele (e.g., Huntington’s Disease). Sex - linked disorders are associated with genes on sex chromosomes (e.g., Duchenne Muscular Dystrophy on the X - chromosome).
• Examples:
• Cystic Fibrosis: Recessive single - gene disorder. Caused by mutations in the CFTR gene, leading to thick mucus in lungs and digestive system.
• Huntington’s Disease: Dominant single - gene disorder. Caused by a mutation in the HTT gene, leading to progressive brain cell death and movement/cognitive issues.
• Duchenne Muscular Dystrophy: Sex - linked (X - linked recessive) single - gene disorder. Caused by mutations in the DMD gene, leading to muscle weakness and degeneration.

2. Multifactorial Disorders

• Description: Caused by a combination of multiple genes and environmental factors (e.g., diet, lifestyle, exposure to toxins).
• Example: Alzheimer’s Disease: Likely involves multiple genetic (e.g., APP, PSEN1 genes) and environmental factors (e.g., aging, head injuries), leading to memory loss and cognitive decline.

3. Chromosomal Disorders

• Description: Caused by changes in chromosome number or structure (e.g., extra, missing, or rearranged chromosomes).
• Example: Down Syndrome: Caused by an extra copy of chromosome 21 (trisomy 21), leading to intellectual disability, distinct facial features, and developmental delays.

4. Mitochondrial Disorders

• Description: Caused by mutations in mitochondrial DNA (inherited from the mother), affecting cells with high energy needs (e.g., nerve, muscle cells).
• Example: Leber hereditary optic neuropathy: Caused by mutations in mitochondrial DNA, leading to vision loss due to damage to the optic nerve.

Answer:

Single Gene (Recessive, Dominant, Sex - linked)

• Description: Caused by mutations in the DNA sequence of a single gene. Recessive: 2 mutated alleles needed; Dominant: 1 mutated allele needed; Sex - linked: associated with sex chromosomes.
• Examples: Cystic Fibrosis (recessive, CFTR gene mutation, thick mucus); Huntington’s Disease (dominant, HTT gene mutation, brain cell death); Duchenne Muscular Dystrophy (X - linked recessive, DMD gene mutation, muscle degeneration).

Multifactorial

• Description: Caused by multiple genes + environmental factors.
• Example: Alzheimer’s Disease (multiple genes + aging/environment, memory loss).

Chromosomal

• Description: Caused by changes in chromosome number/structure.
• Example: Down Syndrome (trisomy 21, extra chromosome 21, intellectual disability).

Mitochondrial

• Description: Caused by mitochondrial DNA mutations (maternal inheritance).
• Example: Leber hereditary optic neuropathy (mitochondrial DNA mutation, optic nerve damage, vision loss).