Unilateral polymicrogyria with ipsilateral cerebral hemiatrophy: a distinct syndrome?

There are sporadic reports of unilateral polymicrogyria with ipsilateral hemiatrophic cerebri associated with epilepsy, focal neurological deficit and mental retardation. The mechanisms which cause this condition are not well understood. The aim of our study was to delineate further, clinical and neuroimaging features of this malformation of cortical development and to explore its possible etiological background.

Four patients (two males and two females), aged from 23 to 31 years (mean age range 27.5 years) were evaluated. Subjects underwent clinical, electrophysiological, neuropsychological and high resolution magnetic resonance imaging assessment.

No significant perinatal event or exposure to intrauterine infection was noted. None suffered from birth asphyxia or ischemic injury. The parents of two patients were first cousins. Every subject had delayed developmental milestones, mental disability and congenital, non-progressive, spastic hemiparesis. They had epilepsy with seizure-onset ranging from three months to 17 years (mean 6.8 years); two had intractable seizures. In all patients, unilateral, right-sided polymicrogyria was associated with ipsilateral cerebral hemiatrophy. Polymicrogyria involved mainly anterior perisylvian areas; occipital regions were relatively spared.

The evaluated patients showed homogenous clinical and neuroimaging characteristics. We support the idea that the disorder could constitute a clinical entity with an underlying genetic cause.