Lissencephaly Flashcards
Lissencephaly
- “Smooth brain”
- Genetic malformation of the cerebral cortex in which abnormal neuronal migration in early development results in smooth cerebral surfaces with absent (agyria) or decreased (pachygyria) convolutions.
- In children, characterized by seizures, cognitive dysfunction, poor feeding, and spasticity
![](https://s3.amazonaws.com/brainscape-prod/system/cm/515/018/244/a_image_thumb.jpg?1626653906)
Miller-Dieker syndrome
- Inherited form of lissencephalopathy
- Due to a microdeletion on chromosme 17
- 80% de novo, 20% inherited
- Agyria and dysmorphic features
Isolated lissencephaly sequence
- Milder phenotype of lissencephaly compared to Miller-Dieker syndrome
- Pachygryria, mild or absent dysmorphic features
- LIS1 form: AD on chr17. Pachygyria is primarily posterior
- Doublecortin form: X-linked. Pachygyria is primarily anterior
Subcortical band heterotropia
- A radiographic finding
- Band of heterotropic gray matter located just beneath the cortex and separated by a thin wall of normal white matter
![](https://s3.amazonaws.com/brainscape-prod/system/cm/515/018/247/a_image_thumb.jpeg?1626654297)
Infantile spasms
- Dramatic, repetitive bouts of rapid neck flexion, arm extension, hip and knee flexio, etc, often with arousal from sleep
- Parents may describe them as unprovoked startle responses or colicky spells due to abdominal pain, but without crying
- Typical presentation between 3-8 months of age
![](https://s3.amazonaws.com/brainscape-prod/system/cm/515/018/250/a_image_thumb.png?1626654435)
Hypertelorism
Abnormally increased distance between the eyes
![](https://s3.amazonaws.com/brainscape-prod/system/cm/515/018/251/a_image_thumb.jpg?1626654516)
Epicanthal fold
Skin fold of the upper eyelid covering the medial corner of the eye
![](https://s3.amazonaws.com/brainscape-prod/system/cm/515/018/252/a_image_thumb.jpg?1626654570)
Clinodactyly
- Congenital condition where the little finger is curved towards the ring finger
![](https://s3.amazonaws.com/brainscape-prod/system/cm/515/018/255/a_image_thumb.jpg?1626654610)
Treament for lissencephaly
- ACTH or prednisone to prevent infantile spasms (used with varying success)
- Feeding tube and gastrostomy to prevent aspiration long-term (aspiration and pneumonia are a common cause of death)
- Physical therapy and muscle relaxants to slow the development of spasms and contractures, which may cause falls, atelectasis, decubitus ulcers
- Treatment of congenital heart and kidney anomalies
Genetic counseling in lissencephalopathy
Recurrence risk is very low for most cases, as most mutations are de novo.
However, if a recpirocal translocation is identified, recurrence risk can be as high as 33%
Diagnosis of lissencephaly
-
In utero:
- Karyotyping, FISH, amniocentesis, chorionic villus sampling
- Imaging for cerebral gyral malformations (if beyond 28 weeks)
-
In a child:
- Neuroimaging
- FISH
Clinical hallmarks of Miller-Dieker syndrome
- Microcephaly with abnormal fascies
- Motor delay (with spasms)
- Cognitive delay
- Seizures
__ can mimic infantile spasms, but will always occur after a child eats, and the child will typically be developmentally normal
Intestinal colic can mimic infantile spasms, but will always occur after a child eats, and the child will typically be developmentally normal
This might make you suspect intussusception