Dynamic Gait Analysis in Children With Mucopolysaccharidosis Type IVa

Mucopolysaccharidosis Type IVa (MPS IVa, Morquio Disease) is a rare inherited lysosomal storage disorder caused by deficiency of the enzyme galactose-6-sulfatase. Children with this disease accumulate a chemical called keratan sulphate, which stops their skeletons developing properly. They are very short in stature and many of their joints are unstable. Children with MPS IVa walk in a different way to other people due to a combination of lax ligaments and skeletal problems such as knock-knees. Human walking involves the coordinated movements of all four limbs. As we walk, the arms swing oppositely to the legs. This movement pattern is very different in children with MPS IVa. This change seems to involve the whole musculoskeletal system and depends on the severity of the disease. Recent studies in children with MPS IVa describing walking pattern have concentrated solely on the lower or upper limb respectively, and have not looked at the interaction of the upper and lower limbs during walking. To our knowledge, the mechanics of walking in children with MPS IVa has not been investigated using a dynamic gait analysis tool (using cameras, sensors and electrodes to track the movements of different parts of the body during walking) and we aim to characterise this in a small number of children with MPS IVa and also examine the effects of splinting the wrist upon the walking pattern to see if this simple intervention makes it easier or more difficult for children with MPS IVa to walk.