A partial autosomal trisomy characterized by developmental delay and intellectual disability, generalized hypotonia, postnatal growth retardation, variable brain and heart anomalies and dysmorphic features, including frontal bossing, round face, full cheeks, low-set ears, broad nasal bridge, short nose with anteverted nares, long philtrum, thin upper lip vermilion, and everted, thick lower lip. Unspecific associated congenital anomalies have also been reported.

An abnormal configuration of the lower lip such that it is turned outward i.e., everted, with the Inner aspect of the lower lip vermilion (normally opposing the teeth) being visible in a frontal view.