P2.065: Hereditary Folate Malabsorption: an uncommon cause of anemia in infants

Introduction: Hereditary folate malabsorption is a rare genetic disorder that can go undiagnosed if no suspected in infants with anemia, delaying treatment and increasing probability of neurologic consequences.

Case Description: We report a case of a 3 months old girl evaluated in ER with complaint of poor oral intake, vomiting and generalized erythematous papular rash with laboratories showing hemoglobin in 6.5 mg/dl, Hct 20.6% and MCV 98.6 fL. She was admitted with diagnosis of anemia, received two blood transfusions with resolution of anemia. Iron deficiency anemia secondary to milk protein allergy was suspected at that moment, for which was discharged on ferrous sulfate and amino acid base formula. One month later, she presents to ER with same symptoms with hemoglobin in 6.2 mg/dl, Hct: 16.8%, MCV 82.5 fL and thrombocytopenia (76 10^3/uL). While admitted she received two blood transfusions, bone marrow biopsy was done with findings of megaloblastic anemia. Folate level was in 6.6 ng/ml, for which she was discharged with diagnosis folate deficiency anemia in treatment with leucovorin 5 mg twice daily. Patient was doing well until 10 months of age, where she presented to ER with somnolence and decrease oral intake with anemia (Hgb 4.1 g/dl / Hct 11.5%) and thrombocytopenia (31 10^3/uL). She received blood and platelet transfusion with resolution of symptoms. She was evaluated by geneticist with genetic test with mutation in gene SLC46A1. Final diagnosis of hereditary folate malabsorption was given and leucovorin dose was increased to 50 mg daily. Patient was evaluated by neurologist with normal neurologic evaluation and Brain MRI. Patient’s development and percentiles for weight, height and head circumference were always adequate for age. Hereditary folate malabsorption (HFM) is a rare autosomal recessive genetic disorder with approximately 60 cases described worldwide.

Discussion: HFM is characterized by folate deficiency with impaired intestinal folate absorption. In the first months of life, infants with HFM usually are asymptomatic due to adequate stores of folate, becoming depleted of folate and presenting symptoms around 2-6 months of age. Clinical findings include failure to thrive, GI symptoms (diarrhea, anorexia), anemia, thrombocytopenia and neurologic manifestations as seizures and developmental delay. Early treatment with adequate dose of leucovorin is important to prevent neurologic symptoms.

Conclusion: HFM despite that is uncommon, should be in the differential diagnosis of infants presenting with anemia and gastrointestinal symptom in early months of life, to begin treatment early and prevent complications.