title: The 0.1% of the population with glucokinase monogenic diabetes can be recognized by clinical characteristics in pregnancy: the Atlantic Diabetes in Pregnancy cohort.
abstract: OBJECTIVE
  Identifying glucokinase monogenic diabetes (GCK-MODY) in pregnancy is important, as management is different from management for other forms of gestational diabetes mellitus (GDM) and there is no increased maternal risk of type 2 diabetes. We calculated the population prevalence of GCK-MODY in pregnancy and determined the clinical characteristics that differentiate pregnant women with GCK-MODY from those with GDM.
  
  
  METHODS
  We calculated the population prevalence of GCK-MODY in pregnancy by testing a subset of patients from the population-based Atlantic Diabetes in Pregnancy (Atlantic DIP) study (n = 5,500). We sequenced for GCK mutations in 247 women with a fasting glucose ≥5.1 mmol/L and 109 randomly selected control subjects with normal fasting glucose. Using data from the cases found and 40 previously identified GCK-MODY pregnancies, we analyzed whether clinical criteria could be used to differentiate GCK-MODY from GDM.
  
  
  RESULTS
  Four women with fasting glucose ≥5.1 mmol/L were diagnosed with GCK-MODY. No cases were identified with normal fasting glucose. The population prevalence of GCK-MODY is 1.1 in 1,000 (95% CI 0.3-2.9 in 1,000) and prevalence in GDM is 0.9% (95% CI 0.3-2.3). Fasting glucose and BMI significantly differentiate GCK-MODY from GDM (P < 0.0001). Combined criteria of BMI <25 kg/m(2) and fasting glucose ≥5.5 mmol/L has a sensitivity 68%, specificity 96%, and number needed to test of 2.7 women with GDM to find one case of GCK-MODY.
  
  
  CONCLUSIONS
  Our large population cohort of pregnant women tested estimates the population prevalence of GCK-MODY of 1.1 in 1,000. We have shown routine clinical criteria that can identify which women should be tested for GCK-MODY in pregnancy.
authors.affiliation: Corresponding authors: Andrew T. Hattersley, a.t.hattersley@exeter.ac.uk.
authors.forename: Ali J
authors.initials: AJ
authors.lastname: Chakera
authors.forename: Gill
authors.initials: G
authors.lastname: Spyer
authors.forename: Nicola
authors.initials: N
authors.lastname: Vincent
authors.forename: Sian
authors.initials: S
authors.lastname: Ellard
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Hattersley
authors.forename: Fidelma P
authors.initials: FP
authors.lastname: Dunne
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D016022:Case-Control Studies; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology; D016640:Diabetes, Gestational / Q000097:blood / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005215:Fasting; D005260:Female; D005941:Glucokinase / Q000235:genetics*; D006801:Humans; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000175:diagnosis*; D011254:Pregnancy in Diabetics / Q000097:blood / Q000175:diagnosis* / Q000235:genetics*; D015995:Prevalence; D012307:Risk Factors; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D005941:Glucokinase