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Diminished complications in a non DR3 DR4 family with insulin-dependent diabetes
R G McArthur1, L L Field, J W Yoon
1Julia McFarlane Diabetes Research Unit, Faculty of Medicine, University of Calgary, Alberta, Canada.
Insights
Heredity plays a role in insulin-dependent diabetes mellitus (IDDM). This family study suggests a protective function linked to residual insulin secretion and highlights potential HLA type influence on fetal susceptibility.
Area of Science:
- Endocrinology
- Genetics
- Immunology
Background:
- Heredity is a significant factor in the development of insulin-dependent diabetes mellitus (IDDM).
- Familial clustering of IDDM suggests underlying genetic predispositions.
- Human leukocyte antigen (HLA) associations are well-established in IDDM pathogenesis.
Purpose of the Study:
- To investigate the genetic and immunological factors in a family with multiple affected members with IDDM.
- To explore the role of HLA antigens in the inheritance pattern of IDDM within this family.
- To examine potential protective mechanisms in patients with early-onset IDDM.
Main Methods:
- Clinical case reporting of a family with IDDM.
- Assessment of disease onset and clinical presentation.
- Human lymphocyte antigen (HLA) typing for HLA-DR3 and HLA-DR4 antigens.
Main Results:
- A mother and her two children developed IDDM between 9 and 19 months of age.
- Affected individuals showed no overt complications and required minimal exogenous insulin, suggesting residual beta-cell function.
- The diabetic children shared identical HLA types, but neither they nor their mother possessed the common diabetes-associated antigens HLA-DR3 or HLA-DR4.
Conclusions:
- The findings underscore the importance of heredity in IDDM.
- Residual insulin secretion may confer a protective effect against severe diabetic complications.
- The absence of typical diabetes-associated HLA antigens in this family suggests alternative genetic or immunological mechanisms may influence IDDM susceptibility and fetal outcomes.
Abstract:
A family is reported in which the mother and both of her children developed insulin-dependent diabetes mellitus between 9 and 19 months of age, reflecting the importance of heredity in the natural history of this disease. That overt complications of diabetes were not present in any of the individuals, and that blood sugars were maintained close to normal on relatively small amounts of exogenous insulin, suggests a protective function in these patients related to residual secretion of insulin by beta cells. Human lymphocyte antigen (HLA) typing in this family showed that, although the diabetic children had identical HLA types, neither the mother nor her children possessed the diabetes-associated antigen HLA-DR3 or HLA-DR4. This raises the possibility that selective loss of diabetes-susceptible fetuses (suggested to be responsible for the low risk of diabetic mothers producing diabetic offspring) may be influenced by the HLA type of the mother.