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disorders of block 2


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Abnormal vertebral regionalization:
-Kioppel-Fiel anomaly

Sacralized/lumbarized vertebrae
Kioppel Fiel
fusion of cervical vertebrae
short neck
low nuchal hair line
sacralized/lumbarized vertebrae
change in TYPE not NUMBER
Assymetry of vertebrae:
Failure of Fusion of neural arches of vertebrae:
Types of dysraphism
rachiscisis - many open

spina bifida - one or a few
mildest spina bifida

worst spina bifida
mildest = occulta

orst = aparta - spinal cord exposed - amniotic fluid
Formation defects of vertebrae:
unsegmented bars
Rib/spine defects
-accessory/fused (lumbar in males most common)

-Malformed sternum/costal cartilage

-Forked ribs
Dysraphic skull frmation:
Suture defects 4
Craniofacial dysostosis
Cloverleaf skull
sutures close prematurely
defect of FGF receptors 1/2
Craniofacial dysostosis
all sutures involved
cloverleaf skull
85% of all cases have additional abnormalities
large calvaria, acrocephalosyndactyly
-Genetic and environmental
-Normal sz face, small calvaria
-brain defects
Craniovertebral junction
Bone fusion or loose ligaments
short neck, low nuchal hairline, restricted head/neck movement
pectoral girdle abnormalities
-cleidocranial dysplasia
-sprengel anomaly
Cleidocranial dysplasia
Hypoplasia, aplasia of clavicles
large head, small face
long/narrow neck
shoulders droop
Delayed fontanelle closure
Incompete pubic development
Sprengel anomaly
Scapula at C4-T2
Usually left, maybe bilateral
Group of disorders characterized by disproportionate growth
-no mental feature
interference with epiphyseal plate development
-Short extremities
-Short stature
-Normal trunk
-Big cranium
-Small face
Normal intelligence
Mutation causing achondroplasia:
FGF receptor 3 gene
Marfan's syndrome
Defective fibrillin production
Autosomal dominant
long digits, aortic aneurysm
eye/spine abnormalities
joint hypermobility
Lysosomal storage disorder
autosomal RECESSIVE
deterioration w/ face and skull distortion
Osteogenesis imperfecta
multiple fractures
Type I collagen defect
Endocrine disorders of skeletal development
OVerproduction of GH
-Gigantism (prepuberty)
-Acromegaly (postpuberty)
skeleta/ear anomalies
-bone age is younger than should be
Muscular malformations - absent
-Absence of sternocostal head of pec major - most common to miss
-Prune belly syndrome - urinary bladder defects
Congenital torticollis
-Fixed rotation/tilt of head
-Trauma during birth
Family of genetic diseases exhibiting progressive deterioration of skeletal muscle but w/o CNS and peripheral nervous pathology:
muscular dystrophy
most common type of MD:
-X-linked recessive
-Muscles lack dystrophin - susceptible to dmg when stressed
Deaths caused by Congenital nervous system malformities:
Fetal = 75%
Infant = 40%
% of all abnormalities:
% of affected embryos aborted during wks 4-8:
Neural tube defects - Dysraphic errors result from
Error in primary neurulation
When primary neurulation occurs:
weeks 3-4
Characteristics of dysraphic errors:
-Faulty NT closure
-Dorsal location
-Midline defects
Supplment that helps prevent dysraphic errors:
-maternal folic acid
Most severe dysraphic error in neural tube devo:
Meroanencephaly - 3 symptoms
-Calvaria missing
-Vascular forebrain/midbrain tissue mass
-High AFP levels diagnostic
skull defect
brain/meninges herniated
cranial meningocoele
only meninges herniated - filled with CSF
cranium bifidum
Skull defect
May/may not be brain or meningeal involvement.
Spina bifida aperta
Neural plate open to surface dorsally (unfused vertebral arches)
90% SB Cystica
Cystic swelling
Spinal cord/meninges herniated usually at lumbar level
SB Cystica 10%
Only meninges herniated
Spina Bifida occulta
Strictly Verteral
-Hair tuft/cyst at defect site
-may confuse w/ diastematomyelia
-10% of adult population
bone spur that teathers spinal cord and prevents ascension
Error of secondary neurulation
abnormal formation of caudal part of spinal cord
-maybe covered w/ pigmented skin
-Midline facial/CNS defects
-Primarily affects forebrain
-50% assoc w/ chromosomal defect
-Alcohol ingestion
Errors of Neuron Proliferation
-Megalencephaly - large head
-Microencephaly - small head
Erros of Neuron Migration
-Agenesis of corpus callosum
-Arnold Chiari
Smooth brain
-Poor responsive in feeding
-Decr. muscle tone
-Devo delay, microcephaly
Small gyri - severe devo delays
Large gyri
-Same sx as microgyria
Agenesis of corpus callosum
may be asymptomatic
increased CSF
noncommunicating hydrocephaly
obstruction in brain - usually at cerebral aqueduct
communicating hydrocephaly
interference w/ resorption
Arnold-Chiari malformation
Caudal displacement and herniation of ventral cerebellar structures
-May be defect in skull base
Duplicated 1st cleft
blind pouch (fistula) runs from ext meatus to cheek
Branchial/cervical cyst
remnant of embryological cervical sinus
Cervical fistula involving 2nd cleft
tracks to tonsilar fossa (thru carotid bifurcation
Cervical fistula involving 3rd cleft
tracks to superior larynx - pierces thyrohyoid
Persistent cervical sinus
opens onto lateral neck anterior to sternocleidomastoid
Abnormal devo of TONGUE
-macroglossia /microglossia
Cause of ankyloglossia:
failure of apoptosis to free tongue from attachment to mouth floor
ankyloglossia is aka
tongue tied
macroglossia/microglossia are often associated with:
downs syndrome
failure of canalization of nasolacrimal duct
Choanal atresia
absence of one or both primitive choanae due to obstruction
What causes choanal atresia?
Failure of oronasal membrane to rupture by 38 days
2 types of abnormal ethmoid bone formation
orbits too close together
orbits too far apart
Cleft lip - uni/bilateral
Failure of fusion of MaxP & MNP
More in Males 2:1
Oblique facial cleft - oroauricular type
Cleft goes from lateral mouth toward ear (auricle)
Wide mouth - macrostomia
Oblique facial cleft - oroorbital type
cleft goes from mouth to orbit
Median cleft lip
hare lip (rabbit)
Cleft palates - morphogenic factors:
-Abnormal tongue devo; it fails to get out of way of palate elevation and fusion
-Cysts - formed from epithelial remnants from left over palate fusion - rupture and reopen palate.
-Impedment of shelf force
Drugs that impede shelf force:
Glucocorticoids - interfere with palatal shelf elevation.
Another name for Mandibulofacial Dystosis:
Treacher Collins syndrome
Features of mandibulofacial dystosis:
-Clefts of arch 1 structures
-Hypoplastic Zygomatic and mandible bones
-Autosomal dominant
Maxillary hypoplasia is aka
Features of Maxillary hypoplasia
-Hypoplastic midface
-Coronal suture synostosis
Mutation causing Crouzon:
FgF receptor 2 on Chr' 10
Mandibular hypoplasia features:
-Small jaw
-Glossoptosis (fwd displacement)
-Difficulty of breathing
-Cleft palate
Heart defects
Atresia (choanal)
Genital hypoplasia
Ear anomalies
2 neural tube defects associated with first arch syndromes:
-Aperts syndrome
Drug that induces facial dysplasia:
Lateral facial dysplasia features:
-Small mouth
-Unilateral facial hypoplasia
-Microtia (small ear)
Agenesis of pharyngeal pouch 1
failure of one or more salivary glands to develop
enlargement of salivary glands due to nonpatent duct
Thyroid agenesis
Pituitary dwarf
Mental deficiency
Persistant thyroglossal duct
-Lingual thyroid
Thyroid Cysts will be located:
anywhere along path of thyroid primordium
-mobile, noncommunic w/ skin
Thyroid fistula
rupture of thyroid cyst
Lingual thyroid
In body of tongue at foramen cecum
Absence of 3/4th pouches:
DiGeorge syndrome
Features of DiGeorge:
-Heart defects
-Minor craniofacial defects
-Hypoplastic mandible
-Cleft palate
Failure of Rathke's pouch to reach posterior portion of pituitary from neural tube
Anomalies of early eye devo:
-Cyclopia to synophthalmia
absence of ocular structures
More common form of anophthalmia
microphthalmia - small eye
(total absence = rare)
Inheritence if isolated
autosomal recessive
primary anophthalmia:
Restricted to eye
surrounding structures develop normally
secondary anophthalmia:
secondary to FOREBRAIN defect
1 eye 1 orbit
multifacial anomalies
2 eyes 1 orbit
2 eyes 2 orbits 1 nostril
Eye structure in
cyclopia: normal or deformed eye

synophth: varied degree of fusion of eyes or close together
sex cyclopia is more common in
Condition associated w/ cyclopia or synophthalmia
Congenital cataract
clouding of the eye
Causes of congenital cataracts
Too much PTH - Intrf w/ eye devo
Congenital glaucoma
increased ocular fluid pressure
Causes of congenital glaucoma
-abnorm devo of fluid draining spacs in eye (junction of sclera and cornea)
Persistent pupillary membrane
persistent hyaloid vessels in front of lens
When hyaloid vessels should regress
4rd trimester
Papillary atresia
persistant pupillary membrane covers pupil
4 types of abnormal eye devo
-Congenital ptosis
mutilation - rare
-notch in 1+ ocular structures -incomplete choroid fissure closure
Congenital ptosis of eyelid
Autosomal dominant
Fail to form Levator Palpebrae
What can cause acquired congenital ptosis
oculomotor nerve injury
decreased eyeball volume
ranges from mild to extreme
Extreme form of microphthalmos:
Anopthalmia - only have eye remnants
Cutoff point for whether function will be abnormal in microphthalmos:
Before 4 weeks - abnormal

After 8 weeks - normal
hidden eye - eyelids absent and eyeball is hidden and malformed
Anotia - microtia
-sex more common in
-side more often on
Range of external ear anomalies
-more common in males
-Right ear more common
Association with anotia/microtia
Fragile X syndrome
Oligohydramnios via kidney abn
Auricular tags
appendages along auricle line of speriolateral migration
Auricular tags associated with:
not associated w/ other anomalies
Auricular sinus
-assoc w/
-Anterior/preauricular to ear
-assoc with kidney anomalies and deafness
Failure of auricle to move superolaterally
-very rare
Sx associated with Otocephaly:
-Severe micrognathia (small mandible)
-Respiratory problems - cause of death
-CNS deformities
-Persistent oral membrane
Mandibulofacial dysostosis - 1st arch abnormalities assoc w/ ext ear abnormalities
-Low set ears
-In addition to facial anomalies
Meatal Atresia/hypoplasia
Absence of patent external auditory meatus
-osseous portion usually involved
Anomalies of middle ear
-congenital fixn of stapes
-ossicle defects
Congenital fixation of Stapes
-Progressive hearing loss
-Autosomal dominant
-Particularly foot of stapes
Ossicle defects
ossicles can be solitary bone
-usually bilateral
Benign growth of endoderm origin
-In the tympanic cavity medial to ear drum
Anomaly of Iner ear
Vestibulocochlear Dysplasia
Vestibulocochlear Dysplasia
-Flattened cochlea
-Decr. # of turns
-Underdevolpd vestibular structures
-Osseous/membranous structures involved too
Largest cause of hearing loss:
Age of diagnosis for congenital hearing loss:
2-3 yrs
3 types of cong hearing loss:
Conduction cong hearing loss:
External and/or middle ear problems - sound not transmitted to cochlea
Sensorineural cong hearing loss:
Inner ear and/or nerve problems
-no signal generated
-thus no transmission to brain
Causes of cong hearing loss:
-Heredity (30-50%)
-Prenatal infxn (rubella, CMV, toxoplasmosis, syphilis, herpes)
-Environmental (thaladomine, acutane)Hypothyroid
-Unknown 30%

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