Multifocal cavitating leukodystrophy-A distinct image in mitochondrial LYRM7 mutations.

An adult woman presented with insidious onset slowly progressive symmetric spasticity and mild upper extremity dysmetria, with sparing of bowel and bladder functions. She had a distinct magnetic resonance imaging (MRI) pattern of bilateral symmetrical T2 hyperintensity involving periventricular especially parieto-occipital and deep cerebral white matter with multifocal small cavitations which were posterior predominant, sparing subcortical U fibres. Magnetic resonance spectroscopy (MRS) showed lactate peak. Her clinical exome sequencing revealed a pathogenic homozygous start-loss variation in exon 1 encoding the mitochondrial LYR motif-containing protein 7 (LYRM7 gene) which is an integral part of complex III of the mitochondrial respiratory chain. Our case was unique in the indolent adult onset leukodystrophy like presentation making her wheel chair bound by the fourth decade, while most reported patients to date had an early childhood presentation as repeated episodes of subacute leukoencephalopathy with motor regression or death by first decade. Myriad phenotypic presentation of the LYRM7 gene mutations reported till date is highlighted.