Pattern of Genetic Inheritance Flashcards
What are the 3 classifications that diseases fall into?
- 100% environmental
- Single gene
- Polygenic
*genetically determined; environmentally determined; 1+2 types
What is Genetic diseases?
- Rare
- Genetics simple
- Unifactorial
- High recurrence rate
What is Environmental diseases?
- Common
- Genetic complex
- Multifactorial
- Low recurrence rate
What are 5 classifications of genetic disorders?
- Chromosomal aberrations
- Multifactorial (Polygenic)
- Single gene (Monogenic)
- Somatic mutations (cancer)
- Atypical Inheritance
What is Euploidy?
Normal 46 chromosomes (2n)
What is Polyploidy?
- Spontaneous abortion
2. Change in the Genome copy number (3n or 4n)
What is Aneuploidy?
- Caused by nondisjunction
2. Changing one chromosome
What is Trisomy numerical abnormalities?
- Compatible with life
2. (2n+1)=47
What is Monosomy numerical abnormalities?
- (2n-1)=45
- Two types:
a. Autosomal (incompatible with life)
b. Sex chromosomal (compatible with life)
- Abnormalities of sex chromosomes are better tolerated than autosomal
- Loss of chromosomal material is more dangerous than gain
What are 8 types of Chromosomal aberrations?
- Down Syndrome
- Edward syndrom
- Patau syndrome
- Klinefelter syndrome
- Turner syndrome
- Cri du chat syndrome (5’ deletion)
- Angelman syndrome
- Prader-willi syndrome
What is polygentic disorders (multifactorial)?
- Most common
- Influence of multiple genes + environmental
- One organ system affected
Ex: Diabetes mellitus, Hypertension, Gout, Schizophrenia
What is Monogenic Disorders?
- 1% of total live births
- Follow Mendelian type of inheritance
- Dominant/recessive pedigree patterns
What is Autosomal Recessive Inheritance Homozygotes?
- With two copies of the altered gene (autosomes) are affected
- Ex: Cystic fibrosis, Sickle-cell anaemia, Phenylketonuria, beta thalssaemia
What is Autosomal Recessive Inheritance Heterozygote?
- With one copy of altered gene and second normal gene are carrier of the disease and have no symptoms
What is Autosomal Dominant Inheritance Heterozygotes?
- With one copy of altered gene are affected
2. Ex: Polycystic kidney disease, neurofibromatosis, Huntington disease