Paternal 20q13.2q13.3 microdeletion syndrome is a recently described syndrome characterized by severe pre- and post-natal growth retardation, microcephaly, intractable feeding difficulties, mild psychomotor retardation, hypotonia and facial dysmorphism.

Distance between nasal base and midline upper lip vermilion border more than 2 SD below the mean. Alternatively, an apparently decreased distance between nasal base and midline upper lip vermilion border.