Seckel syndrome is a type of microcephalic primordial dwarfism that is characterized by a proportionate dwarfism of prenatal onset, a severe microcephaly, a typical dysmorphic face (bird-like), and mild to severe intellectual disability.

Distance from nasion to subnasale more than two standard deviations below the mean, or alternatively, an apparently decreased length from the nasal root to the nasal tip.