Polymicrogyria

Polymicrogyria comes from the greek words poly ( many), micro ( small) and gyri (folds) on the surface of the brain.

It means there are many small gyri packed together. Sometimes they are so tightly packed together they are mistaken for pachygyri or thick and fewer gyri.

When they are bilateral and especially involve the fronto parietal region they may have a genetic basis ( gene identified - GPR56) and have an  autosomal recessive inheritance. Perisylvian polymicrogyria may have AD, AR or XLR inheritence.

Degree of involvement of the brain decides the severity of MR, seizures, developmental delay.

On histopath the cortex may have 1 or 4 layers unlike the ususal 6 layers.

Causes include environmental insults during intrauterine life ( eg CMV or other TORCH infections), genetic disorders ( GRP56 deletion), metabolic disorders ( non ketotic hyperglycenemia, PDH def, glutaric aciduria II def, neonatal adrenoleukodystrophy)

( Ref: Polymicrogyria Overview -

Bernard Chang   http://www.ncbi.nlm.nih.gov/books/NBK1329/)

sturge weber syndrome

Sturge Weber Syndorme is a neurocutaneous syndrome with a facial nevus and angiomas involving the leptomeninges. Glaucoma may or may not be present.
It occurs because of a failure of regression of embryonal blood vessels around the cephalic portion of the neural tube
Neurological dysfunction occurs because of hypoxia, infarction, ischemia, venous occlusion and vasomotor phenomenon in the leptomeningeal angiomas.
Port wine stain in the V1 area of the trigeminal nerve is most likely to have SWS.
Seizures ocur in 75-90%. Glaucoma occurs only if the eyelid is involved.
The port wine stain can be treated with laser therapy.

Basal ganglia calcification on CT

The faint white stippling in the basal ganglia region is calcification.
Calcification is better seen on a CT scan than MRI. MRI will show low intensity on T2 which is often missed. Causes include
1. Metabolic: hypocalcemia due to hypoparathyroidism, pseudohypoparathyroidism and hyperparathyroidism
2. Birth asphyxia
3. Infections: TORCH, CNS TB, CNS HIV, neurocysticercosis, toxoplasmosis
4. Genetic disorders- mitochondrial, Hallervorden Spatz disease
5. Toxins- CO and lead poisoning.
6. Idiopathic- Fahr disease

A good site to read more is :
http://www.ncbi.nlm.nih.gov/books/NBK1421/