DEJERINE-SOTTAS DISEASE WITH DE-NOVO DOMINANT POINT MUTATION OF THE PMP22 GENE

We studied a 33-year-old woman with a negative family history. Both of her parents were examined clinically by nerve conduction velocities ( NCVs) and EMG, with normal results. The clinical onset of her conditio n was at 24 months, with severe weakness and atrophy of her feet and h ands, but the proximal muscles were relatively spared. She had bilater al pes cavus, distal weakness and hypesthesia for touch and propriocep tion, areflexia, claw hands, and severe thoracolumbar kyphoscoliosis. NCVs showed absent motor and sensory responses and EMG revealed diffus e fibrillation potentials. Molecular genetic studies indicated a de no vo dominant missense point mutation of exon 3 of the peripheral myelin protein 22 gene at nucleotide 264 that caused the replacement of seri ne with leucine.