Distal 17p13.3 microdeletion syndrome is a rare partial monosomy of the short arm of chromosome 17 with a variable phenotype characterized by prenatal and postnatal growth retardation, developmental delay, mild intellectual disability, macrocephaly, mild facial dysmorphisms including prominent forehead, hypertelorism, thick upper and/or lower lip vermillion, and structural abnormalities of the brain variably including white matter abnormalities, prominent Virchow-Robin spaces, Chiari I malformation, corpus callosum hypoplasia, but no lissencephaly. The disease is Monarch Disease Ontology entry MONDO_0016839 (distal 17p13.3 microdeletion syndrome). Also known as: distal del(17)(p13.3), distal monosomy 17p13.3.