DIDMOAD SYNDROME - FURTHER-STUDIES AND MUSCLE BIOCHEMISTRY

DIDMOAD or Wolfram (McKusick 222300) syndrome is the acronym for the syndrome of diabetes insipidus, diabetes mellitus, optic atrophy and deafness. Owing to its rarity, most information comes from case reports, which have been adequately reviewed (Cremers et al 1977). The occurrence of symptoms often seen in mitochondrial disorders (deafness, diabetes mellitus, ataxia, retinal pigmentation, episodes of stroke, sideroblastic anaemia), led us to consider whether DIDMOAD might fall into this category (Bundey et al 1992). We described a patient with the syndrome whose muscle biopsy showed abnormal mitochondrial morphology but no ragged red fibres, and normal respiratory chain function but a reduction in the activity of glutamate dehydrogenase (GLUD). Since then, in conflicting evidence, a man has been described with the 11778 'common' mutation of Leber hereditary optic neuropathy (LHON) and DIDMOAD (Pilz et al 1994); a search in muscle, brain and pancreas of another DIDMOAD patient has failed to demonstrate any evidence of a known mitochondrial mutation or rearrangement (Jackson et al 1994). As part of our continuing clinical, biochemical, mitochondrial and genetic studies into this syndrome, we present the respiratory-chain function in three further muscle biopsies analysed in our laboratory, together with available data on three analysed at other centres.