Clinical CharacteristicsOcular Features: Corneal clouding in the form of fine deposits in the stroma is the major ocular manifestation but it may not be noted for several years after birth. Penetrating keratoplasty is rarely needed. Glaucoma occurs rarely. Systemic Features: There is wide variation in the clinical disease in this disorder and some have grouped cases into severe, intermediate and mild categories. Onset is about 2 years of age and three-quarters of patients are diagnosed by the age of 6 years. Intelligence is usually normal and the central nervous system is spared similar to MPS IVB. However, the skeletal dysplasia can lead to neurologic complications. In particular, odontoid hypoplasia raises the risk of atlantoaxial dislocation and spinal cord damage. The maxillary teeth are often abnormal with wide spacing and a flared appearance. Truncal dwarfism is characteristic but the facies are often more fine-featured than in other mucopolysaccharidoses. Lifespan is shortened in most patients. GeneticsThis is an autosomal recessive disorder resulting from mutations in the GALNS gene (16q24.3) encoding galactosamine-6-sulfate sulfatase. Keratan sulfate and chondroitin-5-sulfate accumulates in lysosomes. Urinary keratin sulfate excretion is increased. A clinically similar disease, Morquio syndrome B (253010), is caused by a different mutation. TreatmentTreatment Options: No specific treatment is available for this disease. Some have recommended cervical spine fusion to stabilize the atlantoaxial joint. Orthopedic surgery may be indicated for joint and spine deformities. Special precautions should be taken during intubation for general anesthesia. Enzyme replacement therapies and hematopoietic stem cell transplantation techniques now being developed hold promise for more specific treatment for the underlying enzyme deficiencies in mucopolysaccharidoses. ReferencesArticle Title: Mucopolysaccharidoses and the eye Ashworth JL, Biswas S, Wraith E, Lloyd IC. Mucopolysaccharidoses and the eye. Surv Ophthalmol. 2006 Jan-Feb;51(1):1-17. Review. PubMed ID: 16414358 Glaucoma in siblings with Morquio syndrome Cahane M, Treister G, Abraham FA, Melamed S. Glaucoma in siblings with Morquio syndrome. Br J Ophthalmol. 1990 Jun;74(6):382-3. PubMed ID: 2116163
Mucopolysaccharidoses and the eye Ashworth JL, Biswas S, Wraith E, Lloyd IC. Mucopolysaccharidoses and the eye. Surv Ophthalmol. 2006 Jan-Feb;51(1):1-17. Review. PubMed ID: 16414358
Glaucoma in siblings with Morquio syndrome Cahane M, Treister G, Abraham FA, Melamed S. Glaucoma in siblings with Morquio syndrome. Br J Ophthalmol. 1990 Jun;74(6):382-3. PubMed ID: 2116163
