title: Prevalence of monogenic diabetes in the population-based Norwegian Childhood Diabetes Registry.
abstract: OBJECTIVE
  Monogenic diabetes (MD) might be misdiagnosed as type 1 diabetes. The prevalence of MD among children with apparent type 1 diabetes has not been established. Our aim was to estimate the prevalence of common forms of MD in childhood diabetes.
  
  
  METHODS
  We investigated 2,756 children aged 0-14 years with newly diagnosed diabetes who had been recruited to the nationwide population-based Norwegian Childhood Diabetes Registry (NCDR), from July 2002 to March 2012. Completeness of ascertainment was 91%. Children diagnosed with diabetes who were under12 months of age were screened for mutations in KCNJ11, ABCC8 and INS. Children without GAD and protein tyrosine phosphatase-like protein antibodies were screened in two ways. Those who had a parent with diabetes were screened for mutations in HNF1A, HNF4A, INS and MT-TL1. Children with HbA1c <7.5% (<58 mmol/mol) and no insulin requirement were screened for mutations in GCK. Finally, we searched the Norwegian MODY Registry for children with genetically verified MD.
  
  
  RESULTS
  We identified 15 children harbouring a mutation in HNF1A, nine with one in GCK, four with one in KCNJ11, one child with a mutation in INS and none with a mutation in MT-TL1. The minimum prevalence of MD in the NCDR was therefore 1.1%. By searching the Norwegian MODY Registry, we found 24 children with glucokinase-MODY, 15 of whom were not present in the NCDR. We estimated the minimum prevalence of MD among Norwegian children to be 3.1/100,000.
  
  
  CONCLUSIONS
  This is the first prevalence study of the common forms of MD in a nationwide, population-based registry of childhood diabetes. We found that 1.1% of patients in the Norwegian Childhood Diabetes Registry had MD.
authors.affiliation: KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway.
authors.forename: H U
authors.initials: HU
authors.lastname: Irgens
authors.forename: J
authors.initials: J
authors.lastname: Molnes
authors.forename: B B
authors.initials: BB
authors.lastname: Johansson
authors.forename: M
authors.initials: M
authors.lastname: Ringdal
authors.forename: T
authors.initials: T
authors.lastname: Skrivarhaug
authors.forename: D E
authors.initials: DE
authors.lastname: Undlien
authors.forename: O
authors.initials: O
authors.lastname: Søvik
authors.forename: G
authors.initials: G
authors.lastname: Joner
authors.forename: A
authors.initials: A
authors.lastname: Molven
authors.forename: P R
authors.initials: PR
authors.lastname: Njølstad
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D005260:Female; D005941:Glucokinase / Q000235:genetics; D051538:Hepatocyte Nuclear Factor 1-alpha / Q000235:genetics; D051557:Hepatocyte Nuclear Factor 4 / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009154:Mutation; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics; D012042:Registries; D064233:Sulfonylurea Receptors / Q000235:genetics; D000099161:Kcnj11 Channel
chemical_list: D005941:Glucokinase; D051538:Hepatocyte Nuclear Factor 1-alpha; D051557:Hepatocyte Nuclear Factor 4; D024661:Potassium Channels, Inwardly Rectifying; D064233:Sulfonylurea Receptors; D000099161:Kcnj11 Channel; C577507:ABCC8 protein, human; C496592:HNF4A protein, human