Alpha-mannosidosis: a report of 2 siblings and review of the literature.

Alpha-mannosidosis is a rare lysosomal storage disorder with a heterogeneous clinical presentation. We describe a set of siblings with alpha-mannosidosis. The older child presented with a severe phenotype with multisystem involvement and had progressive deterioration in her motor and cognitive functioning. She had a poor outcome. The second child has a less severe disease course. He is being managed symptomatically only because of the family's poor socioeconomic circumstances. Therapeutic options in this condition are limited to bone marrow transplant early in the disease course. These disorders, although rare, should be considered in the approach to a child with dysmorphism, developmental delay, skeletal deformities, and visceromegaly.