MPS II (Hunter syndrome) is one of 11 mucopolysaccharidoses (MPS) diseases: a group of rare, genetic, metabolic disorders. In this episode, Professor Roberto Giugliani (Department of Genetics of the Federal University of Rio Grande do Sul and Chief of the Medical Genetics Service of Hospital de Clinicas de Porto Alegre, Brazil) discusses the pitfalls of recognising MPS II, a rare and progressive disease. MPS II is difficult to diagnose due to the large heterogeneity in clinical presentations and symptom overlap with common childhood complaints; Professor Giugliani highlights key red flag symptoms for healthcare professionals to be aware of that might prompt clinical suspicion of an MPS disorder. He describes the current diagnostic methods used, including urinary GAG testing, enzyme assays and genetic testing, and discusses the future of GAG testing. He describes the referral network in Brazil as an example to promote earlier referral for testing and earlier diagnosis. This podcast series was initiated, organised and funded by Takeda and is intended for a global healthcare professional audience (ex US, ex UK). Professor Giugliani has received honoraria for this podcast. The views in this episode are those of the speaker, and not necessarily those of Takeda. This information is available for information purposes only; it should not be used for diagnosing or treating a health problem or disease. It is not intended to substitute consultation with a healthcare provider. Please consult a healthcare provider for further advice.