[Non classical subtypes of diabetes mellitus].
BACKGROUND
Some adult, obese and diabetic patients, initiate their disease with a severe diabetic ketoacidosis without a precipitating factor and do not require insulin thereafter. These patients are classified as having a "non classical" diabetes mellitus.


OBJECTIVE
To study the clinical, immunological, genetic and metabolic features of patients with non classical diabetes mellitus.


METHODS
Ten patients (9 men, aged 45 +/- 12 years old) with non classical diabetes mellitus were studied. Anti islet and anti glutamic acid decarboxylase antibodies (ICA and anti GAD), HLA DQ alpha arginine 52 and non aspartic beta 57 were measured. Insulin secretion was measured by C peptide after glucagon injection and with the minimal model of Bergman. The latter model was also used to determine insulin sensitivity.


RESULTS
Three patients were immunologically classified as type 1, since they had positive ICA or antiGAD antibodies and type 1 genetics (neutral or susceptible HLA DQ alpha and beta). They had insulin secretion after glucagon stimulus (C peptide ranging from 2.2 to 7.5 pmol/ml), but an almost absent response to a glucose load. They were also insulin resistant (a sensitivity index ranging from 0.05 to 1.67 x 10(-4) min/microU x ml). These three cases could be categorized as latent type 1. The other seven patients were ICA negative and antiGAD negative. Five had a susceptible HLA genotype for type 1 diabetes and two were neutral. All had insulin secretion after glucagon stimulation and a variable response to glucose. Six were insulin resistant (sensitivity index ranging from 0.32 to 1.29 x 10(-4) min/microU x ml). One patient was insulin sensitive (sensitivity index of 3.83 x 10(-4) min/microU x ml). Therefore all these patients were classified as type two diabetics with an atypical debut.


CONCLUSIONS
Not all diabetics presenting with a severe diabetic ketoacidosis are type I. Among these, there are subjects with a latent type 1 diabetes or with an atypical type 2 diabetes.
Raddatz
V
V
Unidad de Diabetes y Servicio de Urgencia Hospital San Juan de Dios, Servicio de Urgencia Posta Central, Departamento de Endocrinología y Metabolismo, Hospital San Borja Arriarán, Santiago de Chile.
Durruty
P
P
Briones
G
G
López
G
G
Soto
N
N
García de los Ríos
M
M
D001323:Autoantibodies / Q000235:genetics / Q000276:immunology; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D016883:Diabetic Ketoacidosis / Q000235:genetics / Q000276:immunology*; D005260:Female; D005951:Glucose Tolerance Test; D005968:Glutamate Decarboxylase / Q000276:immunology; D006683:HLA-DQ Antigens / Q000235:genetics; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged
D001323:Autoantibodies; D006683:HLA-DQ Antigens; D007328:Insulin; C024211:islet cell antibody; D005968:Glutamate Decarboxylase