Imerslund-Gräsbeck syndrome

Imerslund-Gräsbeck syndrome is an inherited condition that is characterized by problems with the body's ability to take in (absorb) vitamin B12 (also called cobalamin). Most people with Imerslund-Gräsbeck syndrome have a blood disorder called megaloblastic anemia, which occurs when a person has a low number of red blood cells (anemia) and the remaining red blood cells are larger than normal (megaloblastic). Many people with Imerslund-Gräsbeck syndrome have a high level of protein in the urine (proteinuria), but this is less common in affected individuals from Finland. Although proteinuria can be an indication of kidney problems, people with Imerslund-Gräsbeck syndrome typically have normal kidney function.

The signs and symptoms of Imerslund-Gräsbeck syndrome usually begin in early childhood. Megaloblastic anemia leads to many of these signs and symptoms, including an inability to grow and gain weight at the expected rate (failure to thrive), pale skin (pallor), and fatigue. Additional signs and symptoms can include mouth ulcers and gastrointestinal problems, such as vomiting and diarrhea.  Affected individuals may also have recurring respiratory infections.

Imerslund-Gräsbeck syndrome can also cause neurological problems, such as a lack of energy (lethargy); weak muscle tone (hypotonia); developmental delays; problems with movement and balance (ataxia); or abnormal sensations, such as numbness or tingling in the hands and feet. Some affected individuals have more severe neurological signs and symptoms, such as seizures or a decline in intellectual abilities.

Abnormalities of the organs or tissues that make up the urinary tract have been reported in some individuals with Imerslund-Gräsbeck syndrome, but the cause of these problems is not well understood.