Left-sided valvular heart disease and retinopathy in a 38-year-old woman with attenuated mucopolysaccharidosis: a case report.

• A 38-year-old woman with heart failure had heart valve surgery. Examining her cardiac valve tissue under the microscope suggested a metabolic disorder called mucopolysaccharidosis type I (MPS I). • MPS I is due to defective breakdown of sugar molecules (called glycosaminoglycans or GAGs for short) in the body which then can accumulate, causing dysfunction. • Our patient had short stature, a curved spine, stiff joints, and a degenerative eye disease called retinitis pigmentosa, all of which were due to her undiagnosed MPS I. • Most patients with MPS I are discovered on newborn screening when they are babies, or at very young ages due to severe symptoms related to the disease. • Our patient had a form of MPS I that was less severe, and the first symptom she received medical care for was her eye symptoms. • A diagnosis of MPS I made in middle adulthood is unusual for MPS I, and so is an important learning case for providers as there were clues hidden in her medical history that suggested a genetic or inherited syndrome. • Our genetics specialists were able to make a definitive diagnosis of MPS I and begin treatment with enzyme replacement therapy, as well as provide information for the patient about her risk of passing this disease on to children.