LHON MUTATIONS IN ITALIAN PATIENTS AFFECTED BY MULTIPLE-SCLEROSIS

The occurrence of a multiple sclerosis (MS)-like phenotype in subjects carrying mitochondrial DNA (mtDNA) mutations associated with Leber he reditary optic neuropathy (LHON) has suggested that mitochondrial gene s may contribute to susceptibility to MS. With the present study 74 un related Italian patients (53 females and 21 males; mean age 37.9, SD 9 .9, range 20-59) affected by MS with early and prominent optic nerve i nvolvement and 99 normal control subjects were analysed for the presen ce of primary (nps 11778, 3460, 14484) and an alleged secondary one (n p 15257) LHON mutations. A single MS patient carrying a virtually homo plasmic LHON mutation at np 11778 was found. Family history revealed a maternal uncle affected by MS, deceased at age of 64 in consequence o f a stroke. The patient's mother harboured the same mutation in a homo plasmic way. Primary LHON mutations were not detected in any other MS patient or control. Of the MS patients 5.4% (4 out of 74), and 5.1% (5 out of 99) of the controls carried the 15257 mutation in a homoplasmi c state. Present data do not support any contribution of primary LHON mutations to genetically determined susceptibility in MS. There is no evidence that the 15257 mutation has any pathogenetic significance in the Italian population.