Familial diabetes with insulin dependency in later life involving all six members of one generation of a family

The aim of this work was to study the nature of the diabetes affecting six sibs of one generation of a family.

Full clinical histories of all six members of the family were ascertained plus an assessment of beta cell reserve and insulin gene sequencing. Only one member of the family had children and these, and his grandchildren, were investigated for diabetes by glucose tolerance testing and for insulin C‐peptide and proinsulin release to detect possible abnormalities.

Except in one instance, the onset of the disease was gradual and treatment was initiated with diet or oral hypoglycaemic agents. The BMI at onset of diabetes was low. Insulin treatment was required between the ages of 69 and 74. Insulin dosage was generally small and tests on some members of the family revealed residual beta cell function. No abnormalities in carbohydrate metabolism were shown in the children of one member of the family or in his grandchildren. The insulin gene investigated in two members of the family was normal. Antibodies to glutamic acid decarboxylase or tyrosine phosphatase were not detected in the propositus and her niece.

This case report describes familial diabetes progressing to insulin dependency in later life that affected six members of one generation of a family. It is tempting to assume that the diabetes in this family is a consequence of a shared environmental factor. However, it is equally possible that an as yet unidentified gene variant predisposing to diabetes will account for the clinical picture. Copyright © 2001 John Wiley & Sons, Ltd.