2. Congenital Malformations: Failure to Organize

Question 1

Answer 1

Polymicrogyria “PMG”

TORCH infections
toxic exposure
chromosomal issues

With layer 5 gone the other
more superficial layers overfold and fuse resulting in an

“excessive number of small folds”

“Fine undulating / bumpy cortex.”

Zika Virus is the most common cause of PMG in Brazil and South America

Question 2

Answer 2

Schizencephaly - “Split Brain”

Vascular insult = damage the radial glial fibers (in charge of the robes used by neurons to make the climb)

30% of patients = non-CNS vascula sigmata (example = gastroschisis - vascular insult to abdominal wall)

“Split brain” - Cleft (lined with grey matter) connecting teh CSF space with the ventricular system

How wide the cleft is depends on the flavor

Associations: Absent Septum Pellucidum (70%), Focally Thinned Corpus Callosum,
Optic Nerve Hypoplasia (30%), Epilepsy (demonic possession)