Enzyme replacement therapy in an attenuated case of mucopolysaccharidosis type I (Scheie syndrome): a 6.5-year detailed follow-up.

We present the 6.5-year follow-up of a boy with Scheie syndrome whose therapy was initiated at age 2.5 years. Detailed anthropometric features, echocardiography, ophthalmologic and audiologic examinations, psychologic tests, joint range of motion, skeletal radiographs, ultrasound studies of liver and spleen volumes, urinary glycosaminoglycans, and antibodies were documented. After 6.5 years of enzyme replacement therapy, the patient experienced a decline in overall status, and the disease progressed significantly despite treatment. The patient's height at age 9 was equal to that at age 6. The patient developed heart insufficiency and a deterioration of airway flow. The patient's intelligence quotient remained unchanged, i.e., at the average level of 86 on the Terman-Merill Scale. Magnetic resonance imaging revealed cervical spinal canal stenosis and marked spinal cord compression with myelopathy. A worsening of carpal tunnel syndrome was also evident. Ophthalmologic evaluation revealed increased central corneal thickness and intraocular pressure. In audiologic assessment, the patient's results were similar to those after 3 years of treatment. The only benefit involved temporarily improved passive and active shoulder flexion. Overall, the benefit of enzyme replacement therapy with laronidase on Scheie syndrome appeared minimal.