brief explaination corpus callosum agenesis

1. AGENESIS OF CORPUS CALLOSUM
AND
CRANIAL NERVES
PRESENTER
DR. BASAVARAJ.M.M
1ST YEAR RESIDENT
UNDER THE GUIDANCE
DR. ASHOK A
ASSOCIATE PROFESSOR
DEPT OF PEDIATRICS

2. Agenesis of corpus callosum

3. Under the heading
• Anatomy and Development
• Epidemiology
• Causes and Syndrome association
• Sign and symptom
• Diagnosis and Treatment

4. ANATOMY
• Anatomy of cerebral connections
• 3 major type of fiber connections of brain
a. Association fibers- unite different part of same cerebral hemisphere
b. Projection fibers- consist afferent and efferent fibers uniting cortex with lower
parts of brain and spinal cord
c. Commissural fibers- primarily fuction as to join 2 hemispheres
include-corpus callosum,
anterior commissure,&
hippocampal commisure

5. CORPUS CALLOSUM ANATOMY
• It is the largest white matter tract in the brain,with 190 million
myelinated axons crossing the midline to innervate homotopic
structure .
• The development occurs -12th and 20th wks of gestation
Gross anatomy
• Located inferior to the cerebral cortices, and superior to the thalamus
• Connects left and right cerebral hemispheres
• Majority of vascular supply from the ACA branch-pericallosal arteries
• The corpus callosum is approximately 10 cm in length and is C-shaped
(like most supratentorial structures) in a gentle upwardly convex arch.
It is thicker posteriorly.

6. It is divided into five parts (anterior to posterior):
• Rostrum (continuous with the lamina terminalis)
• Genu
• Trunk/Body
• Isthmus
• Splenium
FUNCTION
• Communication between brain
hemispheres .
• Eye movement
• Maintaining the balance of
arousal and attention .
• Tactile localization

7. Epidemiology
• Incidence: 1 in 4000 live birth
• Usually detected after first year of life
• Mothers over age 40 years have 3 fold increase risk compared to
those in their twenties.
• Prematurity is 4 times more common in ACC children
• Non chromosomal ACC associated with 20 % cardiac malformation.

8. CAUSES
• Chromosome errors.
• Inherited genetic factors.
• Prenatal infections or injuries.
• Prenatal toxic exposures.
• Structural blockage by cysts or other brain abnormalities.
• Metabolic disorders.

9. Swaiman’s Pediatric Neurology- Principles and practice

10. Swaiman’s Pediatric Neurology- Principles and practice

11. Signs and symptoms
1. Poor motor coordination,
2. Delays in motor milestones such as sitting and walking,
3. Delayed toilet training,
4. Chewing and swallowing difficulties
5. Vision impairments,
6. Hypotonia
7. Low perception of pain,
Other characteristics sometimes associated with callosal disorders
include seizures, spasticity, early feeding difficulties and/or gastric
reflux, hearing impairments, abnormal head and facial features, and
mental retardation

12. Diagnosis
• Callosal disorders can be diagnosed only through a brain scan
• They may be diagnosed through an MRI, CT scan, prenatal
ultrasound, or prenatal MRI

13. Treatment
• There are currently no specific medical treatments for callosal
disorders, it usually involves management of symptoms and seizures
if they occur.
• Patients may benefit from a range of
– Developmental therapies,
– Educational support, and services.

14. Prognosis
• Prognosis varies depending on the type of callosal abnormality and
associated conditions or syndromes.
• ACC does not cause death in the majority of children.
• Mental retardation does not worsen.
• Although many children with the disorder have average intelligence
and lead normal lives.

15. REFERENCES
• Nelson Textbook of pediatrics –south asia edition
• Swaiman’s Pediatric Neurology- Principles and practice
• Langman’s Medical Embryology
• https://radiopaedia.org/articles

16. AGENESIS OF CRANIAL NERVE
(CONGENITAL CRANIAL DYSINNERVATION SYNDROME)

17. Möbius syndrome
• Bilateral facial weakness, often associated with paralysis of the abducens
nerve.
• Hypo-plasia or agenesis of brainstem nuclei, as well as absent or decreased
numbers of muscle fibers, has been reported.
• C/F: infants present as facial weakness, causing feeding difficulties
owing to a poor suck. The immobile, dull facies might give the incor-
rect impression of intellectual impairment;
• Prognosis :if associated with normal development is excellent in most
cases.
• The facial appearance of Möbius syndrome has been improved by facial
surgery

18. Duane retraction syndrome
• Congenital limitation of horizontal globe movement and some globe
retraction on attempted adduction and is due to abnormal
innervation by the oculomotor nerve of the lateral rectus muscle.
• Abnormalities of cranial nerve development have been demonstrated
in this condition.