Folate deficiency overview

# Overview
Folate deficiency is the deficiency of folic acid, which is a necessary compound for the normal production of red blood cells. Folic acid is part of the vitamin B complex, also called vitamin B9 or pteroylglutamic acid. The recommended daily amount of folate for adults is 400 micrograms (mcg). Adult women who are planning pregnancy or could become pregnant should be advised to get 400 to 800 mcg of folic acid a day. The deficiency of folic acid is associated with a type of anemia, characterized by enlarged blood corpuscles, called megaloblastic anemia.The anemia is thought to be due to problems in the synthesis of DNA precursors, specifically in the synthesis of thymine, which is required for normal erythropoesis and dependent on products of the MTR reaction. Other cell lines such as white blood cells and platelets are also found to be low due to impaired division of the precursor cells.  Bone marrow examination may show megaloblastic hemopoiesis. The anemia is easy to cure with folic acid supplementation.

# Historical Perspective
Folate deficiency was first discovered by Lucy Wills, an English hematologist, in 1931 while conducting seminal work in India in the late 1920s and early 1930s on macrocytic anemia of pregnancy.

# Classification
There is no established system for the classification of Folate deficiency. However, it can be classified into different categories,based on the causative factors.

# Pathophysiology
Folate (also called vitamin B9 or pteroylglutamic acid) is a water soluble vitamin, cannot be synthesized by the human body, however can be obtained from the diet like green leafy vegetables and liver.In the human body folic acid serves a number of functions which include the following :
- Production and maintenance of new cells
- DNA and RNA synthesis
- Carrying one-carbon groups for various methylation reactions
- Preventing changes to DNA, therefore, for preventing cancer

# Causes
Common causes of folate deficiency include gastrointestinal conditions, including malabsorption syndrome and other diseases obstructing folate absorption. Oncological causes, including leukemia, stomach cancer, and liver cancer are life threatening and should be promptly differentiated and diagnosed.

# Differentiating Folate deficiency from Other Diseases
Folate deficiency must be differentiated from other diseases associated with the Macrocytic anemia such as Vitamin B12 deficiency, Alcoholic liver disease, Hypothyroidism, Myelodysplasia and Aplastic anemia.

# Epidemiology and Demographics
The prevalence of folate deficiency is quite variable across the world.Patients of all age groups may develop folate deficiency however primary age groups affected by Folate deficiency include preschool children, pregnant women and older people.

# Risk Factors
Several factors may put a person at risk for developing Folate deficiency.These include the presence of congenital defect, malabsorptive disorder and alcohol abuse. Certain medications use are also associated with higher risk for developing Folate deficiency.

# Screening
Screening for Folate deficiency anemia is usually not routinely recommended for asymptomatic patients.

# Natural History, Complications, and Prognosis
The symptoms of folate deficiency are very non specific and subtle.It can present with the features of anemia and can lead to severe complications if not treated.

## Prognosis
Prognosis of patients with folate deficiency is generally good and clinical and hematological parameters usually reverses after 8 weeks of treatment.

# Diagnosis

## Diagnostic Study of Choice
There is no single diagnostic study of choice or gold standard test for the diagnosis of folate deficiency.

## History and Symptoms
History plays an important role in folate deficiency as the signs and symptoms associated with it are subtle and non specific.

## Physical Examination
Patients with folate deficiency may appear normal in some cases but usually if anemia is moderate or severe, the patient would appear pale,malnourished or underdeveloped. All organ systems can be involved by the effects of anemia.

## Laboratory Findings
Laboratory tests used to diagnose Folate deficiency include complete blood count, peripheral smear, serum LDH level, serum indirect biluribin level, serum folate level, RBC folate level, plasma or serum homocysteine level.

## Imaging Findings
There are no other imaging findings associated with Folate deficiency.

## Other Diagnostic Studies
Bone marrow biopsy, although not done routinely but sometimes can be useful in supporting the diagnosis.

# Treatment

## Medical Therapy
Treatment of folate deficiency includes folic acid supplementation and treating the cause of the folate deficiency.Standard dosing of oral folic acid is 1 to 5 mg/day orally for 1 to 4 months, or until complete hematologic recovery occurs. The oral route is sufficient even in those with malabsorption.
Vitamin B12 deficiency must be ruled out, and treated if present, before giving folic acid to a patient with megaloblastic anemia, since administration of folic acid may worsen neurologic complications of untreated vitamin B12 deficiency.

## Surgery
There is no surgical treatment available for folate deficiency.

## Prevention
Maintaining adequate folate level in the body, is the most effective approach to prevent folate deficiency in states of increased demand such as pregnancy.The source of folic acid to the body is diet. Consuming folic acid rich food will prevent folate deficiency.