[Presence of markers predictive of type I pre-diabetes mellitus status in relatives of patients with type I diabetes mellitus].

Background: The aim of this study was to analyze the predictive factors of IDDM in first degree relatives of IDDM patients.

Subjects And Methods: From 1992 to 1994, 1,053 first degree relatives were screened for measuring islet cell antibodies (ICA) by indirect immunofluorescence (iFl). In all ICA positive subjects, beta cell function was analyzed by intravenous glucose tolerance test (IVGTT) and other immunologic parameters were also studied: anti-insulin antibodies (IAA) by radiobinding and antibodies to glutamic acid decarboxylase (GADAb) by ELISA methods.

Results: ICA were found in 3.1% of the first degree relatives. IVGTT showed a significant decrease in acute first phase of insulin response to glucose (IRI 1 minute + 3 minute) in those with ICA > or = 20 JDF units. In patients with ICA > or = 20 JDF units, 20% were found to be positive for IAA and 40% were positive for GAdAb. Thirty-one percent (10/32) of ICA positive first degree relatives fulfilled prediabetes criteria. During follow-up, 40% (4/10) of these prediabetic patients developed IDDM.

Conclusion: This study confirms the possibility of identifying among first degree relatives of IDDM patients the subgroup with high risk of developing IDDM thus allowing the initiation of therapy for preventing or delaying IDDM onset.