[Familial amyotrophic lateral sclerosis with rapid progression].

We report a family with autosomal dominant (AD) motor neuron disease. A 41-year-old man developed muscle weakness and fasciculation of the lower extremities. The weakness progressed to the upper extremities and bulbar muscles. The cerebrospinal fluid (CSF) protein level was slightly elevated. A nerve conduction study revealed reduced compound muscle action potentials, but conduction block was not observed. Electromyogram showed acute and chronic neurogenic changes. He was treated with intravenous immunoglobulin (IVIg) and methylprednisolone pulse therapy, but his condition rapidly deteriorated. He developed respiratory failure necessitating artificial ventilation within three months after the onset of the disease. His father developed muscle weakness and atrophy of the upper extremities at age 70, and his cousin developed muscle weakness of the legs at age 41. Their conditions rapidly progressed to quadriplegia. CSF and electrophysiological findings were similar to those of the proband. Treatments by steroid pulse therapy, IVIg, and plasmapheresis were not effective. The father and cousin also required artificial ventilation within 3-4 months from the onset of symptoms, and became locked-in state. Autosomal dominant amyotrophic lateral sclerosis (AD-ALS) was considered, but SOD1 gene mutation was not detected. The present pedigree may have familial ALS caused by a gene mutation other than SOD1.