Dyggve-Melchior-Clausen syndrome (DMCS) is an autosomal recessive skeletal dysplasia. Clinical and radiological similarities with Morquio's syndrome can initially lead wrongly to this diagnosis.
Case report: A nine-year-old boy had mental retardation and progressive postnatal dwarfism. Platyspondyly and dysplastic epiphyses and metaphyses resembled those of Morquio's disease; however, clinical and radiological data led to the diagnosis of DMCS.
Conclusion: Clinical and paraclinical features allowing the differentiation of Morquio's syndrome and DMCS are discussed. Initial clinical presentation may be similar, but the intellectual prognosis is different.