Chapter 10 & 12 Flashcards
What are the 3 patterns of single gene inheritance patterns?
- autosomal dominant
- Autosomal Recessive
- X Linked
Autosomal Dominant Traits, transmission and examples
- trait on dominant gene on non-sex chromosome
- can be asymptomatic carriers
- can be transmitted via: men who have offspring in fifties, are carriers and pass new mutation to offspring, can inherit mutations on both genes if both parents are carriers.
- Hutington Disease and Achondroplasia (dwarfism, congenital)
Autosomal Recessive Trait, transmission and examples
- person receives 2 copies of recessive gene
- rare
- recessive disorders are severe, patients usually don’t live long enough to reproduce
- CF and PKU, tay-sachs, sickle cell, and blood groups
- 1/4 chance of having recessive disorder if both parents are carriers
X-Linked recessive traits, transmission and examples
- males usually show full effect of X-linked recessive disorder due to only having 1 X chromosome, only 1 gene is needed
- females carry trait while males are affected
- Females can only inherit if female has single X chromosomal (turners syndrome), or born from affected father and carrier mother.
- Colorblindness, hemophilia
- varying degrees of severity
Numerical Chromosomal Abnormalities
-involved added or missing chromosomes
Trisomy
- numerical chromosomal abnormalities
- extra single chromosome totally 47
- most common is Triosmy 21/down syndrome where there is 3 pairs of chromosome
- risk increased with maternal age >35
Monosomy
- numerical chromosomal abnormalities
- missing single chromosome totally 45
- only condition that is compatible with life is Tuner Syndrome (single x chromosome)
Polyploidy
- numerical chromosomal abnormalities
- one or more extra sets of chromosomes
- results in spontaneous abortion but occasionally seen in live born infant
Structural Abnormalities
-structure of one or more chromosomes may be -abnormal or missing or added DNA or rearranged
Translocation
- part of a chromosome is attached to another
- offspring may receive too much or too little chromosome material at conception or spontaneously in offspring of parents with no translocation.
- Structural abnormalities
Fragile X Syndrome
- Fragile X syndrome is when a area on the X chromosome is weakened and causes intellectual disability.
- Translocation abnormalities
- It is inherited wit the X-Linked dominant pattern.
- Males mostly affected but females can as well but they have 2 X chromosome.
Multifactorial Disorders characteristics and risk for occurrence
- most common birth defect
- caused by interaction of genetic susceptibility and environmental factors during development (such as mother must have inadequate folic acid intake and genetic susceptibility for the child to have spinal bifida.
- can be single, isolated, primary or secondary
- heart defects, neural tube defects, cleft lip and palette, pyloric stenosis
- Factors that affect risk include: number of close relatives, severity of disorder, sex, geographic, seasonal variations
Teratogens
- agents that cause a birth defect or increase likelihood of its development
- infections from viruses/bacteria
- drugs, tobacco, alcohol
- aminioglycosides
- anticonvulsants
- Statins
- anitthyroid
- Folic Acid antagonist
- Lithium
- Mercury
- Tetracycline
- warfarin
- ionizing radiation
- maternal hyperthermia
Rubella Teratogen
-immunization at least 4 weeks prior pregnancy to avoid damage to fetus
Drugs and Other Substances Teratogen
- Class A has no fetal risk
- Class X poses fetal harm
- Avoid Alcohol
- No FDA regulation on botonical products
Ionizing Radiation Teratogen
-radiologic test should be done within first 2 weeks following missed period or have lead on lower abdomen
