Distal Xq28 microduplication syndrome is a rare, hereditary, syndromic intellectual disability characterized by cognitive impairment, behavioral and psychiatric problems, recurrent infections, atopic diseases, and distinctive facial features in males. Females are clinically asymptomatic or mildly affected, presenting mild learning difficulties and facial dysmorphism.

Increased thickness of the lower lip, leading to a prominent appearance of the lower lip. The height of the vermilion of the lower lip in the midline is more than 2 SD above the mean. Alternatively, an apparently increased height of the vermilion of the lower lip in the frontal view (subjective).