Mucopolysaccharidosis (MPS) is an orphan pathology characterized by polymorphism of clinical manifestations and development of typical skeletal changes. However in early childhood the clinical picture is not clear that leads to misdiagnosis and results in inadequate management of patients including unjustified surgical intervention. Early clinical and roentgenologic changes specific to mucopolysaccharidosis IV and VI that enable to suspect the pathology development, to perform required examination with compulsory confirmation by DNA testing results and prescribe vital enzyme replacement therapy as soon as possible are presented. Early diagnosis and initiation of etiotropic treatment and timely correction of the occurring pathology ensure prevention of fatal complications.