Double Heterozygous Germline HNF1A Mutations in a Patient With Liver Adenomatosis

The HNF1A gene is inactivated by mutations in 35% of hepatocellular adenomas (HCAs) (1,2), rare benign liver tumors. In 90% of these HCAs, mutations are biallelic and somatic. In rare cases, one mutation has a germline origin and the second mutation is somatic, thus meeting the genetic criteria of maturity-onset diabetes of the young type 3 (MODY3). Liver adenomatosis (LA) with more than 30 nodules was diagnosed in a 27-year-old patient during the second trimester of a first pregnancy. She has taken oral contraceptives for 10 years and had a slightly abnormal glucose tolerance test at age 18. Gestational diabetes was diagnosed at the 6th month, but she refused insulin therapy and had induced labor at 8 months. Glycemia came back to normal 6 days after delivery and always has been since. Three …