Heather A. Lau, MD, Assistant Professor, Department of Neurology; Associate Director, Division of Neurogenetics; Director, Lysosomal Storage Disease Program at NYU Langone Health, discusses some of the typical patient features across all subtypes of mucopolysaccharidoses (MPSs), a group of rare, inherited lysosomal storage disorders that are clinically characterized by abnormalities in multiple organ systems and reduced life expectancy.

Depending on the mucopolysaccharidoses subtype, affected individuals may have normal intellect or may be profoundly impaired, may experience developmental delay, or may have severe behavioral problems. Many individuals have hearing loss, either conductive (in which pressure behind the ear drum causes fluid from the lining of the middle ear to build up and eventually congeal), neurosensitive (in which tiny hair cells in the inner ear are damaged), or both. Communicating hydrocephalus, in which the normal circulation of cerebrospinal fluid becomes blocked over time and causes increased pressure inside the head, is common in some of the mucopolysaccharidoses. Surgically inserting a shunt into the brain can drain fluid. The eye’s cornea often becomes cloudy from intracellular storage, and degeneration of the retina and glaucoma also may affect the patient’s vision.

Physical symptoms generally include coarse or rough facial features (including a flat nasal bridge, thick lips, and enlarged mouth and tongue), short stature with disproportionately short trunk (dwarfism), dysplasia (abnormal bone size and/or shape) and other skeletal irregularities, thickened skin, enlarged organs such as liver or spleen, hernias, and excessive body hair growth. Short and often claw-like hands, progressive joint stiffness, and carpal tunnel syndrome can restrict hand mobility and function. Recurring respiratory infections are common, as are obstructive airway disease and obstructive sleep apnea. Many affected individuals also have heart disease, often involving enlarged or diseased heart valves.