SURVIVAL MOTOR-NEURON GENE DELETION IN THE ARTHROGRYPOSIS MULTIPLEX CONGENITA-SPINAL MUSCULAR-ATROPHY ASSOCIATION

The survival motor neuron (SMN) gene was lacking in 6/12 patients with arthrogryposis multiplex congenita (AMC) associated with spinal muscu lar atrophy (SMA). Neither point mutation in the SMN gene nor evidence for linkage to chromosome 5q13 were found in the other patients. Hith erto, arthrogryposis was regarded as an exclusion criterion in SMA. Ou r data strongly suggest that AMC of neurogenic origin is genetically h eterogeneous, with a subgroup being allelic to SMA, Absence or interru ption of the SMN gene in the AMC-SMA association will make the diagnos is easier and genetic counselling will now become feasible.