title: Heterozygous missense mutations in the insulin gene are linked to permanent diabetes appearing in the neonatal period or in early infancy: a report from the French ND (Neonatal Diabetes) Study Group.
abstract: OBJECTIVE
  Permanent neonatal diabetes (PND) is defined by chronic hyperglycemia due to severe nonautoimmune insulin deficiency diagnosed in the first months of life. Several genes, including KCNJ11 and ABCC8, which encode the two subunits of the ATP-sensitive K(+) channel (K(ATP) channel) can cause PND. Mutations in the insulin (INS) gene have been recently described in families with neonatal diabetes. Our study aimed to investigate the genetic anomalies and clinical heterogeneity in PND patients who are negative for a K(ATP) channel mutation.
  
  
  METHODS
  We screened the INS gene by direct sequencing in 38 PND patients and in one child with nonautoimmune early-infancy diabetes, where no mutation in GCK, KCNJ11, and ABCC8 was identified. A detailed clinical phenotyping of the patients was carried out to specify the diabetes features in those found with an INS mutation.
  
  
  RESULTS
  We identified three missense mutations in the INS gene in four probands. Two of four mutations were inherited in a dominant manner, and the familial description evidenced a marked variability in age of diagnosis and disease progression. In our cohort, the INS mutations may represent approximately 10% of all permanent neonatal diabetes cases, having a later presentation of diabetes and no associated symptoms compared with cases with K(ATP) channel mutations. CONCLUSIONS; Heterozygous INS gene mutations can cause isolated permanent early-infancy diabetes and should be assessed in neonatal as well as in childhood diabetes appearing like type 1, when autoimmune markers are absent. New pharmacogenomic strategies may be applicable, since residual beta-cell function is still present in some patients.
authors.affiliation: Faculty of Medicine, René Descartes Paris 5 University, Paris, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Polak
authors.forename: Aurélie
authors.initials: A
authors.lastname: Dechaume
authors.forename: Hélène
authors.initials: H
authors.lastname: Cavé
authors.forename: Revital
authors.initials: R
authors.lastname: Nimri
authors.forename: Hélène
authors.initials: H
authors.lastname: Crosnier
authors.forename: Véronique
authors.initials: V
authors.lastname: Sulmont
authors.forename: Marc
authors.initials: M
authors.lastname: de Kerdanet
authors.forename: Raphael
authors.initials: R
authors.lastname: Scharfmann
authors.forename: Yael
authors.initials: Y
authors.lastname: Lebenthal
authors.forename: Philippe
authors.initials: P
authors.lastname: Froguel
authors.forename: Martine
authors.initials: M
authors.lastname: Vaxillaire
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000235:genetics; D007328:Insulin / Q000235:genetics*; D008297:Male; D020125:Mutation, Missense; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D015221:Potassium Channels / Q000235:genetics; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics; D011384:Proinsulin / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics; D011955:Receptors, Drug / Q000235:genetics; D064233:Sulfonylurea Receptors; D000099161:Kcnj11 Channel
chemical_list: D018528:ATP-Binding Cassette Transporters; D007328:Insulin; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011384:Proinsulin; D011498:Protein Precursors; D011955:Receptors, Drug; D064233:Sulfonylurea Receptors; D000099161:Kcnj11 Channel; C013737:preproinsulin