93rd ENMC international workshop: non-5q-spinal muscular atrophies (SMA) – clinical picture (6–8 April 2001, Naarden, The Netherlands)

Abstract

This 93rd SMA workshop followed the European Neuromuscular Centre (ENMC) tradition to combine clinical and molecular topics with the aim of not only exchanging current knowledge but also initiating collaborative studies. Despite important milestones in research on autosomal recessive SMA with localisation on chromosome 5q (SMA 5q) in the past 10 years, we are just beginning to understand the molecular basis and phenotypic spectrum of non-5q-SMA entities. The possibility of analysing the SMN gene allowed the delineation of the diagnostic criteria of ‘classical’ proximal SMA and its clinical variability. On the other hand, different entities of SMA could be defined that show atypical features and proved to be unlinked to chromosome 5q. The field of interest has therefore been focussed on further genes responsible for anterior horn cell loss. This will contribute to further understand the underlying pathogenetic pathways, the complex protein interactions and genotype–phenotype correlations in various types of motor neuron disorders. The workshop was structured in a first part, briefly reviewing the current status of SMA 5q including animal models which have been generated. The second part included different sessions on non-5q-SMA forms; clinical and diagnostic criteria were discussed and adapted to current knowledge. These were summarized by invited chairpersons (named in brackets) and followed by contributions of the participants. The following short summaries cover the essentials of the reviews, the discussion and the consensus achieved. 1. Update on SMA 5q