A 2003 review of 272 MSL cases estimated that 28% of cases were associated withmitochondrial dysfunction, and of the few cases that were genotyped, 16% had a raremitochondrial gene mutation.12 Also, while sporadic MSL is much more common in men, the high proportion ofaffected women in the family reported here confirms that there is no malepredilection associated with the MTTK mutation. The gene discussed is MT-TK; the disease is multiple symmetric lipomatosis.