Maroteaux-Lamy syndrome, mild form--MPS vi b.

Mucopolysaccharidosis VI (Maroteaux-Lamy Syndrome) form B is a rare disease occurring in siblings. It may present with radiological features like Perthes' disease or hypothyroidism. We report two such cases, and discuss the differential diagnosis of the spondylo-epiphyseal dysplasias. We stress the importance of final diagnosis by identifying a particular glycosaminoglycan excess in the urine and an enzyme deficiency in the fibroblasts aryl sulphatase B and N-acetylgalactosamine-4-sulphatase.