Genetic Syndromes & Defects
A child presents with intellectual disability, inappropriate laughter, and ataxia. What is the diagnosis and mechanism behind it?
Angelman syndrome; caused by maternal deletion or mutation on chromosome 15 with imprinting.
What is the definition of epilepsy?
≥2 unprovoked seizures >24h apart
1 unprovoked seizure and a probability of further seizures (60%) after 2 unprovoked seizures, occurring over the next 10 yrs
Diagnosis of an epilepsy syndrome
What do neural crest cells form?
PNS
Describe the function of the arachnoid villi
Resorb CSF into venous sinuses
Which trisomy is associated with holoprosencephaly and postaxial polydactyly?
Trisomy 13 (Patau)
A patient on valproic acid is found to be pregnant. What neural anomaly is the fetus at risk for?
NTDs like spina bifida
What molecular signals initiate neural tube formation, and what is the clinical significance of disruptions in this pathway?
Sonic hedgehog; disruptions can cause holoprosencephaly
A newborn presents with an enlarging head circumference. Imaging reveals dilation of all ventricles without obstruction. What type of hydrocephalus is this?
Communicating hydrocephalus
A previously healthy 2-year-old girl begins to lose speech and motor milestones, develops stereotypic hand-wringing movements, and shows signs of autistic behavior. What is the most likely diagnosis and genetic cause?
Rett Syndrome
A 10-year-old boy is diagnosed with focal seizures. Which antiepileptic drug works by inhibiting voltage-gated sodium channels and is commonly used as first-line treatment for focal seizures?
Carbamazepine
During which weeks of embryogenesis does neural tube closure occur, and what markers (2) are used to detect defect prenatally?
Weeks 3-4; elevated maternal serum AFP and amniotic fluid acetylcholinesterase
Which type of hydrocephalus presents with urinary incontinence, gait disturbance, and dementia?
Normal pressure hydrocephalus
A child presents with an "elfin" facial appearance, intellectual disability, and extreme friendliness toward strangers. What is the diagnosis?
Williams Syndrome
What is the MOA of midazolam?
Midazolam is a benzodiazepine that enhances GABA-A receptor activity by increasing Cl- influx
A newborn presents with myelomeningocele and hydrocephalus. Which CNS malformation is most likely coexisting?
Chiari II malformation
A 24-year-old man presents after head trauma. Imaging shows a lens-shaped (biconvex) hyperdensity that does not cross suture lines. The bleed is located between which two meningeal layers?
Epidural hematoma occurs between the skull and dura mater.
A newborn has tetany, recurrent infections, and a conotruncal heart defect. Genetic testing shows a microdeletion on chromosome 22. What syndrome is this and what embryologic structure is affected?
DiGeorge syndrome (22q11.2 deletion); failure of 3rd and 4th pharyngeal pouch development (thymus and parathyroids).
Infant sits tripod and does a raking grasp. What is the age of the patient based on these developmental milestones?
6 months
Medulla oblongata
What are the major anatomical components of the ventricular system and how does CSF flow through them?
Lateral ventricles --> foramen of Monro --> third ventricle --> cerebral aqueduct --> fourth ventricle --> subarachnoid space