What other congenital cortical malformation is associated with subcortical band heterotopia?
Lissencephaly type I (classic). In fact the two conditions are due to similar mutations and form a spectrum.
Does the predominantly frontal distribution help suggest a specific gene mutation?
The two most common genes involved are DCX gene located on the long arm of chromosome X, which in females tends to produce band heterotopia (in males, lissencephaly) and it has a predilection for the frontal regions of the brain. Posterior predilection suggests mutations of LIS1 [1-2].
Extensive bilateral predominantly frontal and to a lesser degree parietal subcortical thin grey matter bands are seen, with T1 and T2 signal isointense to grey matter. They are separated from the overlying cortex by white matter. Sulcation is normal.