final Flashcards
Crouzon syndrome
- Autosomal dominate; high penetrance. Many causes are due to sporadic mutation; increased risk w/ higher paternal age
- Premature craniosynostosis, may be present at birth
- Coronal fused first in most cases===changes in head and facial form
- Midfacial and maxillary hypoplasia
- Orbital propotosis—protrusion of orbital contents
- Brachycephaly-flat head
- Clinically normal hands
- Measurance alteration in proportions of bones of the hand—shorted proximal phalanx of the first and second fingers. Terminal phalanx of the first finger—short thumbs
Cleidocranial dysplasia
- Autosomal dominat-> CBFA 1 gene a transcription factor
- Multiple unerupted teeth, delayed dental eruption, supernumerary teeth, cementum deficient on roots
- Characteristic facial phenotype: frontal bossing, hypertelorism, delayed closure of fontanels
- Hypoplastic/absent clavicles
**Most common autosomal recessive disorder
Cystic fibrosis 1/22 are carries
v. Amelogenesis Imperfecta
- four genes characterize mutations. Can have different inheritance pattern depending on which is altered.
- Most cases cased by mutation in ENAM and inherited n an autosomal dominant patter
- Autosomal recessive pattern: form of the disorder can result from mutation in ENAM or MMP20
- About 5% of amelogeneis caused by x-linked patter…AMELX
- Shows that specific disorder have multiple pattern evidence
Hemophilia A
X linked recessive disease
- Factor VIII deficiency. Bleeding with minimal trauma , fails to clot
- Bleeding into joins – painful and debilitating
- Require factor replacement prior to dental procedure associated with bleeding
X-linked Dominant
i. Males transmits disease to all of daughters but none of his sons…much less common that other patterns of inheritance
ii. Linked to hypoplastic amelogensis imperfect
iii. More severe form in males, females milder
iv. All daughters of affected man will be affected.
v. Affected females offspring each have 50-50 change of being affected
vi. Hypophosphatemia
hypophosphatemia
- Is a X linked dominant disease
- Recurrent spontaneous dental abscess formation affecting multiple non-carious primary teeth…May also affect perm dentition
- High pulp horns large pulp chambers, dentinal clefts, taurodontism
- Skeletal anomalies…bowing of legs
- Elevated serum alkaline phosphatase, low serum phosphate
- Caused by defective resorption of phosphate in proximal renal tubules and inadequate synthesis of Vit D
Hairy pinna
Y- linked disease( only) transmitted father to sons
since Y never effects daughters
Prader-willis Syndrome
paternal mutation effects both sons and daughter
i. Most common form of obesity caused by genetic syndrome
ii. Affects both sexes and any ethnicity.
iii. Infancy: failure to survive, difficultly eating, hypotonia, poor sucking reflux, diminished or absent cry
iv. Developmental delay….after one year hyperphagia
v. Difficult behavior, short stature, hypogonadism, delayed or incomplete puberty
vi. Learning disabilities and may have mental retardation
Angelman Syndrome
A maternal mutation
i. Consistent (100%): *Developmental Delay, *Speech Impairment, none or minimal use of words, movement or balance disorder
ii. Frequent (>80%): delayed, disproportionate growth in head circumference, usually resulting in *MICROCEPHALy, seizeures, onset by <3
iii. Associated (20-80%): hypopigmented skin/eyes, tongue thrusting, sucking disorder, prominent mandible, increased sensitivity to heat, wide mouth, wide spaced teeth, frequent drooling, protruding tongue, excessive chewing /mouthing behaviors, flat back of head
III. Caudal Regression Syndrome
- ALL IMPORTANT
a. Synonyms: Caudal dysplasia, sacral agenesis, sacral regression
b. CRS strongly ass. With maternal diabetes
c. Defects in the primitive streak in the late gastrula
d. Ingression of mesnchymal cells
CAUDAL regression in gastrulation
- Bc Gastrualation begins in caudal area
i. Congenital anomlaies
ii. Pelvic deformity
iii. Complete or partial agenesis of the sacrum
iv. Femoral hypoplasia ( underdevelopment)
v. Lack of motor function below the level of remaining spin AND sensation tends to be present
chordamesoderm
will form notochord. Rod underneath the neural plate that gives support but also signaling center that directs neuralation
What are the inheritance chromosome abnormalities
Numerical: By number of #
Structural: movement or change in dna/protien
iii. Formation of ring chromosomes
Structural , inheratance chromosome abnormality
lead to epilepsy, mental retardation, dwarfism, microcephaly, turner syndrome (if X-chromo),
1. Symptoms seen in pts carrying ring are more likely to be caused by deletion of gene NOT the formation of ring itself
i. Invagination
sheet of cells (epithelial sheet) bends inward
involution
: epithelial sheet rolls inward to form an underlying layer
Ingression
individual cells leave epithelial sheet and become freely migrating mesenchyme cells
List the classifications of Spina Bifida
a. Spina bifidia occulta ( hidden)
i. One of the mildest forms at times asymptomatic
b. Spina bifida cystica:
cyst protudes through vertebral arch
.c. Menignocele
i. Least common form- CNS undamaged- live long lfe
.d. MYELOmeningocele
i. MOST serious and common form
IX. Arnold Chiari Malformation
Cerebellum deformation associated with spina bifida
Cause: genetic pre-disposition ;also brain or head trauma
What is the most common type of Arnold Chiari Malformation
TYPE-1: Abnormal protrusion of tonsils of cerebellum thru foramen magnum down into cerival spinal canal
Type 0 Arnold Chiari Malformation
i. Obstruction caused by small and malformed posterior fossa (small space in skull, found near the brain stem and cerebellum) w/o evidence of cerebral tonsil herniation
g. Symptoms: headaches, neck pain, balance tolerance, muscle weakness, numbness or other abnormal feeling sin arms or legs, ringing or buzzing in ears
i. When hear these complaints may think TMJ…but taking a good medical history is good b/c TMJ problem shouldn’t also have numbness in fingers and legs
what factors affect neural crest cell migration
i. Permissive factors: Fibronectin and Laminin
ii. Inhibitory factors: Ephrins
iii. Negative chemotaxis: Semaphorins
iv. Positive chemotaxis: Neurogulins
j. differentiation is based on what cells they come in contact with at the target
XII. Waardenburg syndrome
recognize it’s a neural crest abnormality
a. Cleft lip(rare)
b. Extremely pale blue eyes or eye colors that don’t match
c. White patch of hair or early graying of hair
d. Deafness
suture growth
suture growths is perpendicular to suture.
craniosyntosis
a. premature closure of cranial suture
b. primary craniosyntosis = due to abnormality of skull development
i. Isolated or syndromic
c. secondary craniosyntosis = due to failure of brain growth (microcephaly); suture normal but other factors affected
i. Brain development neuralation stage cause suture to fuse bc of growth signals sent to skull
ii. Microcephaly, prematurity, VP shunting, Positioning
a. Deformational Scaphocephaly / Doliochocephaly
MOST COMMON PRemature issue
condition seen in premature babies, SAGITAL suture involved
ii. head is disproportionately long and narrow
iii. results from premature fusion of sagittal suture or from external deformation
iv. Impaired mobility and prolonged positioning
v. Presits into adulthood
vi. Prevention: Donut shaped head supports, waterbed mattress
Fibromatosis Colli
Torticolitis caused by trauma
i. rare form of fibromatosis affecting the sternocleidomastoid muscle
ii. results in most childhood cases of torticollis, due to traumatic birth delivery, or abnormal head position in utero
iii. botox has been used as a treatment to make the neck back to normal- but it could potentially make people less responsive to next anesthesia
iv. can be associated with tumor
what would happen if there is a mutation in MSX-1
Tooth angenesis and cleft palate
Wolf-Hirschhorn syndrome
b. Deletion of the MSX1
c. Phenotypic manifestations:
i. Midline fusion defects (cleft), Ear defects(due to brachial arches), Supernumerary teeth, Microcephaly , distance btw eyes should jump out
IS CONGENITAL
Witkop syndrome
Non-sense mutation of MSX1
b. tooth agenesis and nail dysgenesis
Autosomal dominant
Bezold’s abscess
Rare complication of suppurative mastoiditis occurring when infection erodes the mastoid tip into the neck, forming an abscess
osteoblasts
secrete collagen proteoglycan osteoid
metopic synostosis
triangle head ( trigonocephaly)_
Robertsonian translocation
common form of chromosomal rearrangement that in humans occurs in the five acrocentrice chromosome pairs.
the BMP gradient is responsible for which body axis formation
Dorsal ventral(D-V) axis
what genes are responsible for anterograde-posterior axis development
How Genes
colinearity
also activate by retinoid acid, retinoid receptors
the BMP gradient induces differentiation and growth where
mesoderm and ectoderm
what are the effects of Chordin & Noggin
they bind to BMP growth factors causing BMP activity gradient at gastrula
chord and noggin is associated with
the dorsal side of gastrula
Homeobox genes
control pattern formation and share a consensus sequence
TALE Proteins
binds to DNA 1st then alters the DNA conformation slightly
the cervical vertebra transforms into a throracic vertebrae with ribs is caused by
How genes
paralogy group
How genes organization similar WITHIN A SPECIES… since it develops new functions
Orthology group
Maintain same function throughout evolution in DIFFERENT SPECIES
Rhombomeres :
the pattern of how gene expression often coincide with relative bulges in the sides of rhombencephalon/hindbrain
purpose of Pax 2/5 and Pax6
They are transcription factors subdivide the early neural tube into three divisions..
they also demarcate the midbrain and forebrain primordial at the neural plate stage
what are the importance of the Lim1 and Otx2
seen in anterior mesodermal tissues..
if either is missing embryo does not form a forebrain or midbrain
true or false
retinoid acid can cause cleft palate and micrognathia q
true
Caudal Regression syndrome is associated with what in mother
maternal Diabetes Mellitus
Meningocele
least common form of spina bifida
also called Meningeal cyst
unlikely to suffer longterm damage/nervous system undamaged
Myelomeningocele
Most serious form of spina bifida
Most common form of spina bifida
spinal cord protrudes often resulting in paralysis
Waardenburg syndrome
neural crest abnormality
patient has white hair blue pale eyes or non matching eyes.
deafness
Semaphorins
inhibitory factors in neural crest migration
will actually induce negative chemotaxis to keep cells away
mutation can lead to developmental defects
what is responsible for positive chemotaxis of neural crest cells
Neuregulins
Ephrins are Neural crest ______
Inhibitory factors
