Mondo Description PENS syndrome is a rare, genetic, neurocutaneous syndrome characterized by the presence of randomly distributed, small, white to yellowish, multiple, rounded or irregular polycyclically-shaped, epidermal keratotic papules and plaques of ''gem-like'' appearance with a rough surface, typically located on the trunk and proximal limbs, associated with variable neurological abnormalities, including psychomotor delay, epilepsy, speech and language impairment and attention deficit-hyperactivity disorder. Clumsiness, dyslexia and oftalmological abnormalities have also been reported.