¹Department of Neurology, University Hospital, Nijmegen

²Department of Human Genetics, University Hospital Nijmegen

³Department of Neurology, University Hospital Utrecht

⁴Department of Neurology, Medical Spectrum Twente Enschede, The Netherlands

^aCorresponding author: H. Kremer, Dept Human Genetics, University Hospital Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands. Tel: +31.24.3615296; Fax: +31.24.3540488; Email: H.Kremer@antrg.azn.nl

Spinal muscular atrophies are a heterogeneous group of disorders. They differ in time of onset, clinical presentation, progression, severity and mode of inheritance. In 1985 a Dutch family was described with a dominant, non-progressive spinal muscular atrophy presenting at birth with arthrogryposis (MIM 600175). Linkage analysis was performed in this family. After having excluded the loci for Werdnig-Hoffmann's disease and for dominant distal spinal muscular atrophy with upper limb predominance, we were able to localise the gene to a 10 cM interval between the markers D12S78 and D12S1646 on chromosome 12q23-q24. Recently, dominant scapuloperoneal spinal muscular atrophy has been localised to an overlapping interval. However, the clinical appearances of scapuloperoneal spinal muscular atrophy and the present disorder make allelism unlikely. In 1994, a second Dutch family with a disorder similar to the present one was described. We excluded linkage to markers of the 12q23-q24 region in this family and thereby proved genetic heterogeneity of this type of dominant, congenital and nonprogressive spinal muscular atrophy.

spinal muscular atrophy (SMA); 12q23-24; linkage