Mental retardation, "coarse" face, and hyperbreathing: confirmation of the Pitt-Hopkins syndrome.

We present a patient with distinctive clinical manifestations resembling those first described by Pitt and Hopkins in 1978 [Aust Pediatr J 14:182-184] as a separate entity. Cardinal findings in this syndrome are mental retardation, "coarse" face, and an abnormal breathing pattern. The symptoms in this patient are different from those in the Joubert syndrome, Rett syndrome, Rett-like variants, and of a case reported by Leifer et al. [1991: Dysmorph Clin Genet 5:42-47]. The manifestations in our patient and in the case described by Singh [1993: J Paediatric Child Health 29:156-157] seem to confirm the delineation of this syndrome the cause of which remains unknown.