Safety and Efficacy of Metformin for Treatment of Cytopenia in Children and Adolescents With Fanconi Anemia

Patients will receive metformin immediate-release tablets orally for 24 weeks. Starting dose will be 500 mg once daily for all patients and the dose will be increased by 500 mg weekly until the goal dose is achieved (500 mg twice daily for patients \< 10 years of age, and 1000 mg twice daily for patients 10 years or older)