Transient neonatal diabetes associated with uniparental isodisomy of chromosome 6

A female neonate was born after a 37.4-week pregnancy to a healthy primipara. There was a family history of diabetes on the father's side. The neonate's birth weight was 1,955 g and she was 43 cm long. Physical examination showed bilateral palpebral edema, macroglossia, umbilical hernia and abdominal distension. At 29 hours of life she presented hyperglycemia without acidosis or ketosis. Insulin treatment was started and maintained intermittently until 38 days of life. The patient presented anemia from the second day of life, which required iron therapy and blood transfusion one month after birth. The karyotype was 46, XX with paternal uniparental isodisomy of chromosome 6. Paternal uniparental isodisomy of chromosome 6 has been described as the pathogenic mechanism of transient neonatal diabetes, which provides evidence for an imprinted gene exclusively of paternal expression. In paternal isodisomy (as in regional duplications) there is overexpression due to the existence of two functional copies of the gene, which is responsible for transient neonatal diabetes mellitus. Transient neonatal diabetes associated with macroglossia, umbilical hernia and anemia has been described in only a few cases.