Imerslund-Grasbeck syndrome type 2

Imerslund-Grasbeck syndrome type 2 is an autosomal recessive disorder that affects the body’s ability to absorb vitamin B12. This can lead to megaloblastic anemia, which means that the red blood cells are larger than normal and do not work as well. The condition typically starts in infancy or early childhood and is often associated with low levels of vitamin B12 in the blood. Apart from the anemia, many people with this syndrome may have low levels of certain proteins in the urine (LMW proteinuria) later on. While these kidney findings are usually mild and do not result in worsening kidney function, identifying the correct cause of these symptoms is important to avoid unnecessary treatments.

People with this condition often have vague symptoms including failure to thrive, loss of appetite, fatigue, lethargy, and an increased tendency for infections. The anemia from vitamin B12 deficiency is a primary sign, and low molecular weight proteinuria may appear later in a mild, non-progressive form.

Imerslund-Grasbeck syndrome type 2 is caused by a genetic mutation. It is an autosomal recessive condition, which means that a child must inherit two copies of the mutated gene to develop the disorder. The defect involves a disruption in the AMN gene. This disruption affects the AMN/CUBN complex that forms the cubam receptor, which is responsible for absorbing vitamin B12 in the intestine and reabsorbing proteins in the kidneys.

The main treatment for Imerslund-Grasbeck syndrome type 2 is vitamin B12 supplementation. With proper treatment, the anemia shows steady improvement. The proteinuria seen in this condition is generally mild and does not lead to deterioration of kidney function.

The outlook for people with this condition is generally good if vitamin B12 deficiency is treated effectively. While the anemia improves with appropriate treatment, the mild proteinuria remains non-progressive and does not harm kidney function over time.

Information about research is currently limited for this condition.