PRESENCE OF PREDICTIVE MARKERS OF TYPE-I PREDIABETES MELLITUS IN FIRST DEGREE RELATIVES OF TYPE-I DIABETES-MELLITUS

BACKGROUND: The aim of this study was to analyze the predictive factor s of IDDM in firts degree relatives of IDDM patients. SUBJECTS AND MET HODS: From 1992 to 1994, 1,053 first degree relatives were screened fo r 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 pa rameters were also studied: anti-insulin antibodies (IAA) by radiobind ing and antibodies to glutamic acid decarboxylase (GADAb) by ELISA met hods. RESULTS: ICA were found in 3.1% of the first degree relatives. I VGTT showed a significant decrease in acute first phase of insulin res ponse to glucose (IRI 1 minute + 3 minute) in those with ICA greater t han or equal to 20 JDF units. In patients with ICA greater than or equ al to 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 rela tives of IDDM patients the subgroup with high risk of developing IDDM thus allowing the initiation of therapy for preventing or delaying IDD M onset.