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Questions and Answers
What is a primary issue associated with Anodontia?
What genetic condition is commonly associated with Anodontia?
What characterizes an Anterior Cleft Palate?
What type of cleft results from non-fusion of the palatine shelves of the maxillary prominences?
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What is the prevalence of cleft lip in births?
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What is the primary cause of craniosynostosis?
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Which of the following terms refers to a collection of symptoms frequently occurring together due to a single cause?
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What is the typical closure date for the anterior fontanelle?
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Which craniofacial disorder is characterized by underdevelopment of the orofacial region and is caused by genetic mutations?
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Which type of treatment is commonly used for craniosynostosis?
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What is the likelihood of finding identifiable genetic mutations in patients with craniosynostosis?
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What is associated with high intracranial pressure in craniosynostosis?
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Which biological cells are primarily impacted in conditions like Treacher Collins Syndrome?
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What typically connects the cervical sinus to the pharynx in the case of an internal branchial fistula?
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Which of the following syndromes is commonly associated with Pierre Robin Sequence?
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What is the mechanism that leads to glossoptosis in Pierre Robin Sequence?
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In craniofacial microsomia, which factor is primarily responsible for the asymmetric malformation?
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What are the potential additional symptoms associated with craniofacial microsomia?
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Which treatment is commonly recommended for individuals with supernumerary teeth?
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What is a leading cause of supernumerary teeth initiation?
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What is a common treatment outcome for reconstructive surgery in craniofacial microsomia?
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What is a common presentation feature of 22q11.2 Deletion Syndromes related to facial structures?
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What type of surgical intervention is typically required for individuals with cleft palate?
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Which gene is significantly affected in 22q11.2 Deletion Syndromes?
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What is a common result of ankyloglossia?
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What condition is characterized by a failure to close the pharyngeal clefts, specifically noted in pharyngeal cleft 2?
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Which of the following is a typical treatment for individuals with calcium deficiency due to thymus underdevelopment in 22q11.2 Deletion Syndromes?
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What is the primary surgical intervention for managing a thyroglossal cyst?
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What sensory-related issue might individuals with 22q11.2 Deletion Syndromes experience?
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Study Notes
Craniosyntosis
- Premature closure of cranial sutures
- Occurs in 1/2,500 births
- Can be isolated or a part of a syndrome
- Results in:
- Abnormal head shape
- Increased pressure on the brain (intracranial pressure) that can impact neural development
Sutures & Fontanelles
-
Sutures – where 2 bones meet
-
Fontanelles – where 3+ bones meet
-
Allow movement of skull bones during birth
-
Remain open for brain growth
### Fontanelle Location Closure Date -
Anterior Frontals & Parietals 13–24 months
-
Posterior Parietals & Occipital 1–2 months
-
Mastoid Parietal, Temporal, & Occipital 6–18 months
-
Sphenoid Sphenoid, Parietal, Temporal, Frontal 6 months
Craniosyntosis: Etiology
- Genetic mutations (identified in 20–30% of patients)
- Environmental factors play a likely role
Craniosyntosis: Mechanism
- Neural crest cells (NCC) - mesoderm derived cell boundary disintegration
- Abnormal cell specification
- Premature loss of mesenchymal stem cells
Craniosyntosis: Treatment
- Surgical intervention (high risk)
- Postoperative helmet therapy (maintenance)
Treacher Collins Syndrome
- Autosomal dominant genetic disorder
- Caused by mutation in TCOF1, POLR1D, POLR1B, POLR1C genes
- Often a new mutation
- Occurs in 1/50,000 births
- Hypoplasia (underdevelopment) of the orofacial region
- Highly variable presentation
Treacher Collins Syndrome: NCC Defect
- Reduction in the number of neural crest cells (NCC)
- Neural crest cells form:
- Viscerocranium
- Cartilage, bone, dentin, tendon, dermis, sensory neurons, glandular connective tissue
Treacher Collins Syndrome: Presentation
- Hypoplasia of facial bones
- Mandible, maxilla, zygomatic
- Cleft palate
- External & internal ear defects
- Conductive hearing loss
- Eye defects
- Coloboma, palpebral fissure angle, eyelid droop, vision issues
- Tooth defects
- Respiratory issues – tongue obstruction
Treacher Collins Syndrome: Treatment
- Hearing aids
- Corrective surgery
- Urgent respiratory surgical needs
- Varying ages for palate, facial, ear, and tooth based on maturation
22q11.2 Deletion Syndromes
- Deletion of long arm (q-arm) of chromosome 22
- Occurs in 1/4,000 births
- Occurs during meiotic rearrangements
- Affects TBX1 gene
- Expressed in all germ layers of the pharyngeal arches (PA)
- Communicates with neural crest cells (NCCs)
- Highly variable presentation
22q11.2 Deletion Syndromes: Mechanism
- Significant impact on 3rd & 4th pharyngeal pouches
- Hypoplasia or lack of thymus & parathyroid glands
- Remodeling of pharyngeal arteries
- Affects mesenchyme- epithelial interactions
- Significant impacts on cortical brain development
22q11.2 Deletion Syndromes: Presentation
- Heart defects
- Palatal abnormalities
- Facial anomalies
- Immunodeficiency
- Learning & behavioral disabilities
- Speech and hearing deficiencies
- Frequent ear infections
- Increased risk of psychiatric disorders
22q11.2 Deletion Syndromes: Treatment
- Surgical repair
- Aggressive infection treatment
- Calcium supplements
- Therapy and educational support
Ankyloglossia (Tongue-Tied)
- Frenulum extends to the apex of tongue
- Absence of normal cell degeneration
- Restricts tongue movement
- Typically stretches
- Therapy
- Surgical removal
Thyroglossal Cyst
- Remnant of thyroglossal duct
- Can occur anywhere along thyroid migration path
- Commonly near hyoid
- Occurs in the midline
- Can occur anywhere along thyroid migration path
- Infection
- Low risk of cancer
- Sistrunk procedure
- Low rate of recurrence
Branchial Cleft Fistulas/Cysts
- Failure to close pharyngeal clefts
- Most common pharyngeal cleft 2
- Fistula opens anterior to the sternocleidomastoid
- Cyst – just below the angle of the mandible
- Often enlarges during childhood
Internal Branchial Fistula
- Rupture of membrane between the pharyngeal cleft & pouch
- Cervical sinus connected to pharynx
- Typically drains into the tonsillar fossa
Pierre Robin Sequence
- Impacts 1st pharyngeal arch (PA) structures
- Genetic or environmental onset
- Idiopathic origin
- Isolated Robin Sequence associated with chromosomal mutations
- Idiopathic origin
- Occurs in 1/8,500 births
- Often occurs with other syndromes/anomalies
Pierre Robin Sequence: Mechanism
-
Micrognathia (small jaw) → tongue displacement → obstructed closure of palatine shelves
-
Theories:
- Abnormal mandibular growth
- Tongue neuromuscular delay
- Mandibular compression
Pierre Robin Sequence: Symptoms
- Micrognathia (small jaw)
- Glossoptosis: tongue obstructing the posterior pharynx and airway
- Cleft palate
Pierre Robin Sequence: Treatment
- Prone positioning
- NPA – Nasopharyngeal airway tube
- Surgical intervention
Craniofacial (Hemifacial) Microsomia
- Asymmetric malformation of 1st & 2nd pharyngeal arches (PAs)
- Typically unilateral, can be bilateral
- Hypoplasia of the face, ear, eye, teeth, cranial nerves
- Environmental factors, maternal intrinsic factors, genetic mutations
- Occurs in 1/3,500 – 4,500 births
Craniofacial (Hemifacial) Microsomia: Pathogenesis
- Abnormal vasculature or hemorrhaging
- Insufficient blood supply to the face
- Stapedial artery
- Teratogen exposure
- Genetic component
- Disrupted mesenchymal communication
Craniofacial (Hemifacial) Microsomia: Presentation
- Lack of defined criteria/ high variability in phenotype
- Eliminating alternative diagnoses
- Minimum:
- Ipsilateral mandibular and ear dysmorphia
- One of the following + 2 additional unrelated anomalies
- Ocular deformities
- Extracranial defects: cardiac, neurological, skeletal
- Family history
Craniofacial (Hemifacial) Microsomia: Treatment
- Surgical intervention
- Functional first
- Reconstructive
- Surgery mixed results
- Determined by the extent of hypoplasia
- High rates of recurrence
Supernumerary Teeth
- Disruption of initiation stage (tooth development)
- Typically singular
- Typically posterior to the maxillary incisors
- Issues:
- Crowding/displacement
- Failure to erupt
- Malocclusion
Supernumerary Teeth: Mechanism
- Localized hyperactivity of the dental lamina
- Genetic & environmental factors
- Family history increases risk
- Often related to additional syndromes
- Treatment: extraction
Anodontia
- Disruption of initiation stage
- Rarely complete
- Issues:
- Malocclusion
- Speech impediment
- Aesthetics
- Downstream effects of treatment
Anodontia: Mechanism
- Rarely isolated, typically part of a syndrome
- Defect of the dental lamina
- Local, systemic, or genetic
- Strong familial inheritance
- Ectodermal dysplasia
- Treatment: nothing or prosthetics
Facial Clefts: Cleft Palate/Cleft Lip
- Common craniofacial defects
- Difficulties with speech
- Genetic & nongenetic factors
- Cleft palate - incisive foramen
- Border between anterior & posterior clefts
- Can be a combination
- More common in males (1/1,000 births)
Facial Clefts: Anterior Cleft Palates
- Incomplete fusion between the intermaxillary segment and maxillary prominences
- Types:
- Lateral cleft lip
- Cleft upper jaw
- Between primary and secondary palates
Facial Clefts: Posterior Cleft Palates
- Non-fusion of palatine shelves of maxillary prominences
- Too small
- Failure of tongue to drop
- Failure to elevate
- Disrupted fusion process
- Types:
- Cleft (secondary) palate
- Cleft uvula
Facial Clefts: Cleft Lip
- Unilateral or bilateral
- Bilateral – separates the intermaxillary segment from the oral cavity
- Defective orbicularis oris (muscle that closes the mouth)
- Bilateral – separates the intermaxillary segment from the oral cavity
- Cleft Lip with Bilateral Defects: separates the intermaxillary segment from the oral cavity, defective orbicularis oris
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Description
This quiz delves into craniosynostosis, its etiology, and the mechanisms behind premature closure of cranial sutures. Learn about the implications for neural development, head shape abnormalities, and the relevant anatomical features. Test your understanding of this critical topic in cranial health.
