Hereditary folate malabsorption

Hereditary folate malabsorption is a disorder that interferes with the body's ability to use certain vitamins from food. During digestion, the body cannot take in (absorb) certain B vitamins called folates. Folates are important for cell growth and function and blood cell formation.

Infants with hereditary folate malabsorption are born with normal amounts of folates in their body because they get these vitamins through the placenta before birth. Affected babies generally begin to show signs and symptoms of the disorder within the first few months of life when they cannot use the folates they get from food.

Infants with hereditary folate malabsorption often experience feeding difficulties, diarrhea, and swelling or irritation on the inside of the mouth (oral mucositis). These babies also do not gain weight and grow at the expected rate (failure to thrive). Affected individuals usually develop a blood disorder called megaloblastic anemia. Megaloblastic anemia occurs when a person has a low number of red blood cells (anemia), and the remaining red blood cells are larger than normal (megaloblastic). People with hereditary folate malabsorption may also have fewer white blood cells (leukopenia), making them more susceptible to infections. In addition, some affected individuals have fewer platelets (thrombocytopenia), which means they can bruise easily.

Without treatment, affected individuals may develop neurological problems such as developmental delays, intellectual disabilities, seizures, and difficulty coordinating movements (ataxia). Abnormal deposits of calcium (calcification) in the brain may also occur.

Pregnant women with hereditary folate malabsorption who are receiving treatment for the vitamin deficiency do not appear to have an increased risk of having children with birth defects caused by folate deficiency, such as spina bifida or anencephaly.