Non 5q-spinal muscular atrophy (SMA)

Location: Naarden, The Netherlands

The ENMC workshop on Non-5q-SMA took place in Naarden on 6th - 8th April 2001. It was attended by 13 active participants from Belgium, Finland, France, Germany, The Netherlands and United Kingdom.The meeting opened with the re-evaluation of the clinical picture, pathology and electro-physiology of classical SMA linked to 5q. Of special interest were the pathoanatomical features of the two existing SMA animal models for SMA 5q in comparison to the pathology in humans.The major topic was the re-evaluation of so called SMA plus types of childhood including diaphragmatic SMA (SMARD), SMA with (ponto-)cerebellar hypoplasia, SMA with myo-clonic epilepsy as well as the Brown-Vialetto-van Laere syndrome. SMA with arthro-gryposis and congenital fractures was included as a heterogeneous group of disorders. Published cases were reviewed and the definition of certain types was broadened by the discussion of new families.After reviewing the differential diagnoses of autosomal dominant and adult SMA different families were discussed. It turned out that rare autosomal dominant proximal SMA families with onset in adulthood exist. It was agreed that there are pedigrees with congenital autosomal dominant SMA as well. Distal SMA (often referred to as hereditary motor neuropathy) and scapuloperoneal SMA are observed in dominant and recessive families. The distinction of distal SMA and axonal Charcot-Marie-Tooth disease may be impossible in single families. Segmental SMA is a different condition which is usually not inherited.The participants underlined the necessity to define distinct phenotypes and to collect further families with rare Non 5q-SMA entities in order to perform linkage studies and to identify genes involved in different forms of spinal muscular atrophy.

An extended report of this meeting is published in Neuromuscular Disorders, Volume 13, No. 2, February 2003.

Prof. K. Zerres (Aachen, Germany)