Empagliflozin as a Treatment for Severe Congenital Neutropenia Due to G6PC3 Deficiency

Background: Severe congenital neutropenia (SCN) is an immune system disease. People with SCN do not have enough of a kind of white blood cell called neutrophils. This means they get sick easily from infections. Some drugs to treat SCN have lots of side effects. Researchers want to see if a the drug empagliflozin can help increase the number of neutrophils in a person with SCN. Objective: To see if a drug called empagliflozin can help people with SCN. Eligibility: Adults aged 18 and older with SCN. Design: Participants will be screened with a physical exam, medical history, and blood tests. They may have a pregnancy test. Participants will have study visits and local lab visits. They will repeat the screening tests. They will have heart and lung function tests. They will have an ultrasound of the liver and spleen. Their skin symptoms will be photographed. They may have consultations with specialists. They may give a stool sample. They may have an optional colonoscopy with tissue sample collection. They may have an optional bone marrow biopsy and aspirate. They may have an optional magnetic resonance imaging scan of their heart. Participants will be admitted to NIH for 5 7 days. They will start taking the study drug as a pill once daily. They will be monitored for side effects. Participants will take the study drug at home for 12 months. They will use a fingerstick blood glucose meter to measure blood sugar at home. Participants may be able to take the study drug through their local doctor after the study ends. Participation will last for 15 months.