Ch 1 - Developmental Defects 1 Flashcards by Austin Shackelford

What week is the primitive nostril developed?

4th week

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What week is the upper lip developed? What structures merge to make it?

6-7th weeks…medial nasal processes merge with each other and then with the maxillary processs of the 1st branchial arches

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What structures combine to form the primary palate?

medial nasal processes

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The primary palate gives rise to the intermaxillary segment, which then develops into the ______, which is a triangular shaped piece of bone that includes the 4 incisor teeth.

premaxilla

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How much of the hard and soft palate is a result of the “secondary plate”? What structure helped form the secondary plate?

90% of the hard and soft palate…the maxillary process of the 1st branchial arches

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When do the palatal shelves start to fuse? What 2 structures do they fuse with? When is it completed?

8th week…primary palate and nasal septum…done by 12th week

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Defective fusion of the ________ process with the

_______ process leads to cleft lip (CL).

Defective fusion of the MEDIAL NASAL process with the MAXILLARY process leads to cleft lip (CL).

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Failure of the _________ to fuse results in cleft palate (CP).

palatal shelves

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Approximately ___% of cases are CL + CP

45%

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___% of cases are CP only (CPO) and ____% are isolated CL

30% being CP only (CPO) and 25% being isolated CL

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Both isolated ______ and ____ + _____ are thought to be etiologically related conditions and can be considered as a group

cleft lip AND cleft lip + cleft palate

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Isolated ____ appears to represent a separate

entity from CL ± CP

cleft palate only

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more than ___ developmental syndromes have been identified that may be associated with CL ± CP or CPO…..___% of CL ± CP cases and ___% of CPO cases are associated with syndromes

400….30% of CL ± CP and 50% of CPO cases (thus CPO is more likely to be syndromic)

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Maternal ______ consumption has been associated
with an increased risk for both syndromic and
nonsyndromic clefts.

EtOH

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Maternal _______ at least doubles the frequency of cleft development

cigarette smoking

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An increased frequency of cleft development has been related to ________ therapy (especially ______)
which causes a nearly TENFOLD greater risk of cleft formation

anticonvulsant (esp phenytoin)

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A number of studies have suggested that ______ supplementation may play a role in prevention of orofacial clefts.

folic acid (B9)

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The ________ is caused by lack of fusion of the
maxillary and mandibular processes and represents 0.3% of all facial clefts….what is the clinical outcome when the cleft extends from the commissure to the ear?

lateral facial cleft….macrostomia

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What are 4 disorders associated with a lateral facial cleft?

Mandibulofacial dysostosis 2. Oculo-auriculo-vertebral spectrum (hemifacial microsomia) 3. Nager acrofacial dysostosis 4. Amniotic rupture sequence

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The ________ cleft extends from the upper lip to the eye. It is nearly always associated with ________, and severe forms often are incompatible with life.

oblique facial cleft….cleft palate

_________ is an extremely rare anomaly that results from failure of fusion of the medial nasal processes.

Median cleft of the upper lip

Median cleft of the upper lip may be associated with a number of syndromes, including which 2?

oral-facial-digital syndromes

2. Ellis-van Creveld syndrome

Most apparent median clefts of the upper lip actually represent agenesis of the primary palate associated with _________.

holoprosencephaly

Please list the top 4 ethnicities in order of prevalence of CL+/-CP

Native Americans (3.6 / 1000) 2. Asian (1.5 / 700-1000) 3. Whites (1 / 700-1000) 4. Blacks (0.4 / 1000)

Which is more common CL+/-CP or CPO?

CL+/-CP much more common (CPO is 0.4/1000)

(Gender) CL ± CP is more common in _____ than in ______. In fact, The more severe the defect, the greater the _____ predilection

CL ± CP is more common in MALES than in females. The more severe the defect, the greater the MALE predilection

Gender predilection for CPO?

FEMALE (same as CL/CP, the greater the defect of CPO the more FEMALE predilection)

Approximately 80% of cases of CL will be ______ (laterality) with 20% ________...WTF? Approximately 70% of unilateral CLs occur on the _____ side.

unilateral....20% bilateral....left

The minimal manifestation of CP is a ______. What is the prevalence of this compared to CP?

cleft or bifid uvula.... The prevalence of cleft uvula is MUCH HIGHER than that of CP, with a frequency of 1 in every 80 white individuals.

What two populations have a much higer rate of bifid uvula?

Native Americans and Asians

A ______ is when the surface mucosa is intact, but a defect exists in the underlying musculature of the soft palate

submucous palatal cleft

Which cleft can appear as a BLUISH midline discoloration?

submucous palatal cleft

What are the three components of the Pierre Robin sequence?

1. "U-shaped" Cleft palate 2.mandibular micrognathia 3.glossoptosis

What are the two most commonly associated genetic disorders with the Pierre Robin sequence?

1.Stickler syndrome 2. VeloCardioFacial syndrome (DeGeorges)

What is unique about the shape of the palatal cleft in the Pierre Robin sequence?

its U-shaped

In nonsyndromic cases of orofacial clefting, the risk for cleft development in a sibling or offspring of an affected person is ___-___% if no other first-degree relatives also are affected...The risk increases to __% to ___% if other first degree relatives are affected.

3% to 5%....10% to 20%

__________ are small mucosal invaginations that occur at the corners of the mouth on the vermilion border...What failed to fuse?

Commissural lip pits...embryonal maxillary and mandibular processes

Commissural lip pits are more common in what age group? Gender? Suggestive inheritence pattern?

adults (considered congenital, but develop later in life)...MALES...AD

While commissural lip pits are not associated with clefts, they might be associated with _______ (what other clinical finding of the face)

preauricular pits (aural sinuses)

What are 2 alternate names for Paramedian Lip Pits?

1. Congenital fistulas of the lower lip 2.congenital lip pits

__________ are rare congenital invaginations of the lower lip. How do they form?

Paramedian lip pits...persistent lateral sulci on the embryonic mandibular arch (normally dissappear at 6 weeks of embryonic age)

What is the term for paramedian lip pits in association with CL/CP?

Van der Woude Syndrome

What is the most common form of syndromic clefting?

Van der Woude syndrome

Gene mutations for Van der Woude syndrome? (chromo?)

IRF6 chromo 1q32-q41

What are two other syndromes (besides Van der Woude) that feature paramedian lip pts?

1. Popliteal pterygium syndrome | 2. Kabuki syndrome

Which syndrome is closely related to Van der Woude syndrome?

Popliteal pterygium syndrome

What are the 5 features of poplitral pterygium syndrome?

1. Paramedian lip pits 2. pterygia (poplital webbing) 3. CL+/-CP 4. genital abnormalities 5. sygnathia (congenital bands fusing upper and lower jaws)

_______ syndrome received its name because affected patients exhibit eversion of the lower lateral eyelids

Kabuki

What are the 7 characteristics of Kabuki syndrome?

1. paramedian lip pits 2. intellectual disability 3. large ears 4. CL+/-CP 5. Hypodontia 6. Joint laxity 7. Skeletal abnormalities