How Mutations Affect Health and Craniofacial Development Flashcards
How many de novo mutations are children normally born with that were not present in the parents?
100-200
Rate of children born with a diagnosable genetic condition that can be attributed to a single major mutation?
1 in 50
What is aneuploidy?
aberration in chromosome number caused by faulty segregation of chromosomes during mitosis or meiosis
Ratio of babies born with aneuploidy
1 in 400
Where does aneuploidy most commonly occur?
in female meiosis 1
-increased risk with maternal age
Examples of aneuploidy with oral manifestations:
-down syndrome
-edwards syndrome
-mosaic 22 trisomy
-turner syndrome
-etc
What is down syndrome?
trisomy 21
-full or partial extra chromosome 21
-in in 700 babies in the US
-most common chromosomal condition
What causes trisomy 21?
-nondisjunction >95% of cases
-mosaicism around 1% of cases: least common form
-translocation around 4% of cases
What is the only factor that has been associated with increased chance of having baby with Down syndrome?
maternal age
-however this is not always a good indicator
is heredity a factor in trisomy 21?
no not really
(1% of cases)
Signs of down syndrome:
-low muscle tone
-small stature
-cognitive delay
-transverse palmar crease
What are the three things you must ask being treating a patient with Down syndrome?
-do they have any heart defects
-do they have any spinal problems
-do they have seizures
Individuals with Down syndrome are at risk for:
-heart defects
-spinal problems atlantoaxial instability)
-GI defects
-immune disorders
-sleep apnea
-obesity
-leukemia
-dementia
-endocrine problems
-dental problems
-seizures
What causes chromosomal rearrangments?
chromosome breakage or by recombination between mispaired chromosomes during meiosis
What type of chromosomal rearrangements cause disease?
those that change copy number of genes or that break up an important gene
