title: A dizygotic twin pregnancy in a MODY 3-affected woman.
abstract: BACKGROUND
  MODY diabetes includes rare familiar forms due to genetic mutations resulting in β-cell dysfunction. MODY 3 is due to mutations in the gene transcription factor HNF-1α, with diabetes diagnosis in adolescence or early adult life. Few data are available about MODY 3 in pregnancy.
  
  
  METHODS
  A 36-year-old Italian woman came to our unit at the 5th week of pregnancy. She was diagnosed with diabetes at 18 years, with negative autoimmunity and a strong familiarity for diabetes. She was treated with gliclazide and metformin. She had a previous pregnancy in which she was treated with insulin, giving birth at 38 weeks to a 3.210 kg baby girl, who showed neonatal hypoglycemia. We switched her to insulin treatment according to guidelines. We asked for genetic molecular testing, resulting in a HNF-1α gene mutation. A US examination at 7 weeks revealed a twin, bicorial, biamniotic pregnancy. At 37 weeks of gestation, she gave birth to two normal-weight baby girls; only one showed neonatal hypoglycemia and a genetic test revealed that she was affected by HNF-1α gene mutation. Subsequently, entire family of the woman was tested, showing that the father, the sister and the first daughter had the same HNF-1α mutation.
  
  
  CONCLUSIONS
  A MODY 3 foetus needs a near-normal maternal glycemic control, because the exposure to intrauterine hyperglycemia can lead to an earlier age of diabetes onset. Neonatal hypoglycemia is generally observed in MODY 1 infants, but it is possible to hypothesize that some HNF-1α mutations could lead to a functionally impaired protein that might dysregulate HNF-4α expression determining hypoglycemia.
authors.affiliation: Department of Clinical and Molecular Medicine, Sapienza University, Rome, Italy. olimpia.bitterman@gmail.com.
authors.forename: O
authors.initials: O
authors.lastname: Bitterman
authors.affiliation: Department of Paediatrics, Second University of Naples, Naples, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Iafusco
authors.affiliation: Department of Gynecology, Sapienza University, Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Torcia
authors.affiliation: Department of Molecular Medicine and Medical Biotechnology, Naples - CEINGE Advanced Biotechnology, Federico II University, Naples, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Tinto
authors.affiliation: Department of Clinical and Molecular Medicine, Sapienza University, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Napoli
mesh_terms: D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D051538:Hepatocyte Nuclear Factor 1-alpha / Q000235:genetics; D006801:Humans; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000175:diagnosis*; D011272:Pregnancy, Multiple
chemical_list: C496487:HNF1A protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha
keywords: HNF-1α; Hypoglycemia; MODY 3; Twin pregnancy