Background: Diagnosis of rare diseases or disorders is understandably challenging because it is unfeasible for practicing physicians to make themselves familiar with hundreds of rare diseases. The diagnosis of rare inherited metabolic syndromes such as mucopolysaccharidoses is additionally complicated by the lack of confirmatory sophisticated laboratory tests in many areas of the world. In the more developed countries, the diagnosis of mucopolysaccharidoses depends on urine tests for excessive mucopolysaccharides and enzyme assays. However, these tests are not easily accessible in countries like Iraq, and the diagnosis has to rely on clinical and radiological findings. Case Report: The clinical and radiologic diagnosis of an Iraqi patient with Maroteaux-Lamy syndrome is described. The clinical diagnosis of the girl with early-onset mucopolysaccharidosis and the abnormalities were recognizable before the age of two. The clinical and radiologic diagnosis was Maroteaux-Lamy syndrome because of the absence of mental retardation and the presence of hepatosplenomegaly. Conclusion: Clinical diagnosis of rare metabolic syndromes like mucopolysaccharidoses requires magnificent clinical skills and huge experience because of the similarity between various types of mucopolysaccharidoses.