Mild fasting hyperglycemia in children: high rate of glucokinase mutations and some risk of developing type 1 diabetes mellitus.
BACKGROUND
Incidental hyperglycemia in children generates concern about the presence of preclinical type 1 diabetes mellitus (T1DM).


OBJECTIVE
To genetically evaluate two common forms of maturity-onset diabetes of youth (MODY), the short-term prognosis in children with mild hyperglycemia, and a positive family history of diabetes mellitus.


METHODS
Asymptomatic children and adolescents (n = 14), younger than 15 yr, with fasting hyperglycemia, a positive family history of mild non-progressive hyperglycemia, and negative pancreatic autoantibodies were studied.


METHODS
Glucokinase gene (GCK) and hepatocyte nuclear factor 1 alpha gene (HNF1A) causing two common forms of MODY were sequenced. The clinical outcome was evaluated after a follow-up period of 2.8 +/- 1.3 yr.


RESULTS
GCK mutations were present in seven children. The confirmation of this diagnosis allowed discontinuation of insulin in two families and oral medications in three families. Mutations of HNF1A were not detected in any of the families. During the follow-up period, all the GCK mutation carrier children remained asymptomatic without medication and the last hemoglobin A1c levels were 6.4 +/- 0.7%. In the GCK-negative children (n = 7), one developed T1DM, corresponding to 7.2% of the total group. Mild fasting hyperglycemia persisted during follow-up in four GCK-negative children and normalized in the remaining two.


CONCLUSIONS
The presence of mild persistent hyperglycemia in any patient without autoantibodies should lead to genetic analysis of GCK, particularly if there is a positive family history. Furthermore, those without GCK mutations should be followed with repeat autoantibody testing, and other genetic types of diabetes should be considered if hyperglycemia worsens.
Codner
Ethel
E
Institute of Maternal and Child Research (IDIMI), School of Medicine, University of Chile, Santiago, Chile. ecodner@med.uchile.cl
Rocha
Ana
A
Deng
Liyong
L
Martínez-Aguayo
Alejandro
A
Godoy
Claudia
C
Mericq
Verónica
V
Chung
Wendy K
WK
D000293:Adolescent; D001724:Birth Weight; D001786:Blood Glucose / Q000032:analysis; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000453:epidemiology* / Q000235:genetics*; D005190:Family; D005260:Female; D005941:Glucokinase / Q000235:genetics*; D006442:Glycated Hemoglobin / Q000378:metabolism; D051538:Hepatocyte Nuclear Factor 1-alpha / Q000235:genetics; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000150:complications* / Q000235:genetics*; D008297:Male; D009154:Mutation; D010375:Pedigree; D018570:Risk Assessment
D001786:Blood Glucose; D005941:Glucokinase; D006442:Glycated Hemoglobin; D051538:Hepatocyte Nuclear Factor 1-alpha; C496487:HNF1A protein, human