How Do Mutations Affect Health & Craniofacial Decelopment (Exam IV) Flashcards
The average child is born with an estimated _______ new mutations that were not present in the parents
100-200
1 in 50 infants is born with a diagnosable genetic condition that can be attributed to a:
Single major mutation
Chromosome disorders include (5):
Aneuploidy, rearrangements/translocations, deletions, insertions & duplications
Single gene disorders include:
Dominant, recessive & codominant
Multifactorial or complex genetic disease occur due to:
Multiple genes or gene-environment
What are the three types of genetic diseases:
1- chromosomes disorders
2- single gene disorders
3- Multifactorial/complex disorders
An aberration in chromosome number caused by fault segregation of chromosomes during mitosis or meiosis
Aneuploidy
Aneuploidy occurs as a result of:
Faulty segregation of chromosomes
_______ infants is born with Aneuploidy
1 in 400
Most cases of Aneuploidy originate in:
Female meiosis I
The risk of Aneuploidy occurring in female meiosis I:
Increases with maternal age
Down syndrome displays:
Oral manifestation of Aneuploidy
Describe the key facial characteristics of Down syndrome (6):
1- upslanting palpebral fissures (upward eye slant)
2- low-set, small, folded ears
3- short neck
4- flattened nasal bridge
5- brushfield spots
6- epicanthal fold
Down syndrome is also called:
Trisomy 21
Most common chromosomal condition
Down syndrome
How many babies per year are born with Down syndrome
1 in 700 in the US
(Around 6000 babies per year)
Down syndrome is a result of:
Full or partial extra copy of chromosome 21
Down syndrome can occur through:
1- nondisjunction
2- mosaicisim
3- translocation
When chromosomes do not separate appropriately during meiosis
Nondisjunction
Makes up greater than 95% of Down syndrome cases
Nondisjunction
Makes up about 1% of Down syndrome cases- the least common form
Mosaicism
Makes up about 4% of Down syndrome cases
Translocation
When the egg is fertilized & has the appropriate number of chromosomes to starts, but later during different mitosis there is failure of the chromosomes to split properly
Mosaicism
Down syndromes cases caused by translocation occur due to a full or partial copy of chromosome 21:
Attaching to another chromosome
Most common chromosome for chromosome 21 to attach to during translocation
Chromosome 14
The only factor that has been linked to having an increased change of Down syndrome resulting from Nondisjunction or Mosaicism
Maternal age
Due to higher birth rates in younger women, 80% of babies born with Down syndrome are born to women:
Under 35 years of age
5% of Down syndrome cases have been traced to the:
Father
_____ is not a factor in trisomy 21 (Nondisjunction) & Mosaicism
Heredity
In 1/3 of cases of Down syndrome resulting from translocation there is a ____ component
Hereditary (around 1% of all cases)
Describe the muscle tone & stature of an individual with Down syndrome
Low muscle
Small stature
Cognitive delay in a an individual with Down syndrome can be:
Mild to severe