This is the third of a four-part series focusing on alpha-mannosidosis. In this episode, we feature Dr. Markey McNutt, who will focus on the challenges of identifying and caring for patients with this rare disease. Dr. McNutt is a Clinical Geneticist at the University of Texas Southwestern Medical Center in Dallas.Alpha-mannosidosis is a rare genetic disorder characterized by a deficiency of the enzyme alpha-D-mannosidase. Alpha-mannosidosis is best thought of as a continuum of disease that is generally broken down into three forms: a mild, slowly progressive form (type 1); a moderate form (type 2); and a severe, often rapidly progressive and potentially life-threatening form (type 3).The symptoms and severity of the disorder are highly variable. Signs may include distinctive facial features, skeletal abnormalities, hearing loss, intellectual disability, and dysfunction of the immune system. Alpha-mannosidosis is caused by mutations of the MAN2B1 gene. This genetic mutation is inherited as an autosomal recessive trait.