First phase insulin release and glucose tolerance in children with Fanconi anemia after hematopoietic cell transplantation

Abstract

Fanconi anemia (FA) is an autosomal and X-linked recessive disease of chromosomal instability, which results in bone marrow failure. Children with FA have been shown to have an increased risk of diabetes mellitus (DM). A cross-sectional study of glucose and insulin metabolism was conducted in 17 children with FA who had undergone hematopoietic cell transplantation (HCT) at the University of Minnesota. First phase insulin release (FPIR) was determined by intravenous glucose tolerance test (IVGTT). Oral glucose tolerance test (OGTT), lipid panel, blood pressure, and medical history were reviewed for additional metabolic abnormalities. Seventeen FA participants, median age 11.3 (range 5.5-17.6) years, were evaluated. IVGTT identified three separate groups: low FPIR, normal FPIR, and high FPIR. Those with low FPIR were more likely to have low BMI, but had normal glucose levels. Those with high FPIR, had high BMI, elevated lipids, and body fat. One patient with normal FPIR had impaired glucose tolerance and another with normal FPIR had impaired fasting glucose. No participant was diagnosed with DM by fasting glucose, 2 hr glucose during OGTT, or hemoglobin A1C. The majority of children with FA had normal glucose tolerance and normal beta-cell function after HCT. Two small subsets of patients had lower than expected and higher than expected FPIR. The clinical significance of these differences is not yet known given the normal glucose tolerance and fasting glucose levels in these two groups.