Genetic Disorders - Complex Multigenic and chromosomal nomenclature Flashcards
What type of inheritance do complex multigenic disorders have?
Multifactorial inheritance
environment + 2 or more genes
What is multifactorial inheritance?
Environment + 2 or more gene interactions
What type of inheritance do complex multigenic disorders have?
Multifactorial inheritance
environment + 2 or more genes
What is the most common cause of congenital malformation?
Multifactorial inheritance
What are examples of complex multigenic disorders?
Cleft palate, cleft lip, neural tube defects
Common symptoms of complex multigenic disorders?
Range of levels of severity
What are complex multigenic disorders commonly confused with?
Mendelian
How many chromosomes do humans have?
23 pairs = 46
- 22 pairs of autosomes
- 1 pair of sex chromosomes
Euploid
Multiple of 23
Aneuploid
NOT an exact multiple of 23
What 2 things can cause Aneuploid?
Nondisjunction
Anaphase lag
Nondisjunction gametes will have +/- ___ chromosome
1
Anaphase lag gametes will have?
1 normal cell and 1 monosomy cell
Can you give birth if the child has monosomy?
NO
Mosaicism
2 or more populations of cells with different chromosomal complement
In what chromosomes is Mosaicism common?
Sex chromosomes
Ring Chromosome
Breaks at each end of a chromosome with fusion of the remaining ends to form a ring
2 types of Inversion?
Paracentric
Pericentric
Paracentric Inversion?
Inversion of 2 pieces on 1 arm of the chromosome
Pericentric Inversion?
Inversion of 2 pieces on opposite arms of chromosome
Isochromsome
1 arm of chromosome is lost
= 2 short or 2 long arms ONLY
Balanced Reciprocal Translocation
Single breaks in 2 chromosomes that perfectly exchange material
= NO LOSS OF MATERIAL
Is there loss of material with Balanced Reciprocal Translocation?
NO
Balanced Reciprocal Translocations have a ___ phenotype, but?
Normal
= Increased risk of producing abnormal gametes
Robertsonian Translocation
Translocation between 2 chromosomes, breaks appear really close to centromere
= 1 large chromosome and 1 small that is lost
End result of a Robertsonian Translocation?
1 large chromosome and 1 small one that is usually lost
What chromosomal disease can occur via Robertsonian Translocation?
Trisomy 21