Ring chromosome 18 syndrome is an autosomal anomaly characterized by variable clinical features, most commonly including hypotonia, neonatal feeding and respiratory difficulties, microcephaly, global developmental delay and intellectual disability, growth hormone deficiency, hypothyroidism, hearing loss, aural atresia, dysmorphic facial features and behavioral characteristics. The disease is ring chromosome 18 (MONDO_0015434). Also known as: Chromosome 18 Ring, Ring chromosome type 18.