Genetic testing for maturity onset diabetes of the young in childhood hyperglycaemia
- aDepartment of Paediatrics, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK, bDepartment of Vascular Medicine and Diabetes Research, Postgraduate Medical School, Exeter EX2 5AX, UK
- Dr Dunger. email:david.dunger{at}paediatrics.oxford.ac.uk
- Accepted 24 November 1997
Abstract
Mild hyperglycaemia is a common finding during minor illness in children. The differential diagnosis includes maturity onset diabetes of the young (MODY), which can be a difficult diagnosis to make clinically. As most genes resulting in MODY have been identified, it is possible to make a firm diagnosis using mutation detection. A case is reported of a 4 year old girl in whom a diagnosis of MODY2 was established by the finding of a heterozygous missense mutation in exon 7 of the glucokinase gene, resulting in the substitution at codon 259 of alanine by threonine (A259T). Observations from other glucokinase families suggest that hyperglycaemia in this child is likely to be stable and will not require intensive medical follow up, whereas other forms of MODY (1, 3, and 4) might carry a different prognosis.
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Maturity onset diabetes of the young is an important diagnosis to consider in a child with incidental hyperglycaemia.
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If considered, parents’ fasting blood glucose should be measured. If raised, molecular genetic testing may be useful.
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Molecular genetic testing has defined four different phenotypes of MODY with different clinical courses and prognoses.
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MODY2, resulting in defects of the glucokinase gene, carries a good prognosis.
