1qter deletion syndrome is a chromosomal anomaly characterized by an intellectual deficiency, progressive microcephaly, seizures, growth delay, distinct facial dysmorphic features and various midline defects including cardiac, corpus callosum, gastro-oesophalgeal and urogenital anomalies. The disease is MONDO_0018205 (distal monosomy 1q). Also known as: distal deletion 1q, distal monosomy type 1q, monosomy 1qter, telomeric deletion 1q.