Imerslund-Gräsbeck syndrome

Imerslund-Gräsbeck syndrome (IGS), also known as selective vitamin B12 malabsorption with proteinuria, is a rare autosomal recessive disorder characterized by megaloblastic anemia and proteinuria. The syndrome was first described by Olga Imerslund in Norway and Ralph Gräsbeck in Finland, hence the name Imerslund-Gräsbeck syndrome.

Etiology

IGS is caused by mutations in either the AMN or CUBN genes. These genes are responsible for the production of proteins that work together to absorb vitamin B12 in the small intestine. Mutations in these genes disrupt the absorption process, leading to vitamin B12 deficiency.

Clinical Features

The main clinical features of IGS include megaloblastic anemia and proteinuria. Megaloblastic anemia is a condition characterized by larger than normal red blood cells and a decreased number of red blood cells. Proteinuria is a condition where an excess amount of protein is present in the urine. Other symptoms may include fatigue, weakness, pallor, and failure to thrive in children.

Diagnosis

Diagnosis of IGS is based on clinical features, laboratory tests, and genetic testing. Laboratory tests may show low levels of vitamin B12 in the blood, megaloblastic anemia, and proteinuria. Genetic testing can confirm the diagnosis by identifying mutations in the AMN or CUBN genes.

Treatment

Treatment for IGS involves lifelong vitamin B12 injections to correct the deficiency. With regular treatment, individuals with IGS can lead normal, healthy lives.

Epidemiology

IGS is a rare disorder, with an estimated prevalence of 1 in 200,000 to 1 in 1,000,000. It is more common in certain populations, such as the Finnish and Norwegian populations, due to a higher frequency of the disease-causing mutations in these populations.

See Also

• Megaloblastic anemia
• Proteinuria
• Vitamin B12 deficiency

NIH genetic and rare disease info

• NIH info on Imerslund-Gräsbeck syndrome

Imerslund-Gräsbeck syndrome is a rare disease.

Imerslund-Gräsbeck syndrome Resources
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