Mitochondrial abnormalities are not invariably present in neurologic syndromes associated with multiple symmetric lipomatosis

Familial multiple symmetric lipomatosis (MSL) associated with neurologic disease has been described in several reports. Recently, MSL has been associated with morphologic changes in skeletal muscle or genetic evidence of mitochondrial DNA (mtDNA) mutations, particularly the base pair (bp) 8,344 MERRF mutation [1,2]. However, it is unclear whether MSL or the associated neurologic disease are invariably associated with such mitochondrial abnormalities, either inherited or acquired. In 1990 we described a familial syndrome of axonal peripheral neuropathy with MSL [3]. Four of seven surviving siblings of one generation (II-2, II-7, II-8, and II-9) were affected Figure 1in Chalk et al [3]). Both parents were deceased, but they had not displayed multiple lipomata. We examined many of our patients' offspring (III-1 to III-8; IV-4 and IV-5) and found no MSL or neuropathy Figure 1in Chalk et al [3]). On the basis of this pedigree, we felt that inheritance was most likely to be on an autosomal recessive basis. However, the recent reports linking MSL with mtDNA abnormalities prompted us to note that our family's pedigree was also consistent with a maternal inheritance pattern. In view of this possibility, we have studied muscle histology and biochemistry and mtDNA extracted from muscle and a lipoma removed at plastic surgery from patient II-9 for evidence of mitochondrial disease. Methods. Cytochrome oxidase and citrate …