[Phenotypes in ALS--clinical features and pathology].
Typical amyotrophic lateral sclerosis (ALS)/motor neuron disease (MND) is not hard to diagnose, but when it comes to atypical forms of MND which account for about 20% in clinical setting, we may face some difficulties in differentiating clearly between atypical forms of ALS/MND and other non-ALS diseases, such as multifocal motor neuropathy, chronic inflammatory demyelinating polyneuropathy and cervical spondylosis. There is striking phenotypic variation in sporadic ALS/MND, i.e. flail arm syndrome (brachial amyotrophic diplegia), pseudopolyneuritic form, hemiplegic type, ALS/MND with markedly extended involvement beyond the motor system, MND with basophilic inclusion bodies, spinal progressive muscular atrophy, primary lateral sclerosis, progressive bulbar palsy and motor neuron disease with dementia. These variations must be recognized when physicians are to tailor advice on disease progression, prognosis, drug therapy, and care to the needs of the individual. Clinical trials of new therapeutic agents have been performed, on the assumption that patients with ALS/MND have the same underlying etiology, addressing the heterogeneous population of the patients under a single diagnostic category. This can be detrimental to the well-being of the individual, because clinical heterogeneity may mask drug effects in clinical trials. The attempt to categorize subgroups based on the clinical and pathological background within the spectrum of ALS/MND may be a critical step in facilitating clinical research in ALS/MND. Definition of clinicopathologic syndromes in patients with ALS/MND is an important challenging task. It will be necessary to accumulate motor neuron disease cases with phenotypic variation and analyze them clinically and pathologically to elucidate whether various kinds of subgroups of motor neuron diseases lie on the same spectrum of ALS.
Sasaki
Shoichi
S
Department of Neurology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
D000690:Amyotrophic Lateral Sclerosis / Q000145:classification / Q000175:diagnosis / Q000209:etiology / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D010641:Phenotype