Kugelberg-Welander disease is one of a group of disorders referred to as spinal muscular atrophies (SMA); Kugelberg- Welander disease is SMA Type III. It is characterized by degeneration of the anterior horn cells of the spinal cord. It becomes evident between 2 and 17 years of age. Kugelberg- Welander disease is believed to be genetically homogeneous and associated with chromosome region 5qll.2-13.3. It is an autosomal recessive disorder and is usually evident in cousins or siblings, although the parents are usually asymptomatic. There is an equal incidence in males and females; there is no evidence that Kugelberg-Welander disease is more evident in any one ethnic group. The presence of Kugelberg-Welander disease can be determined from diagnostic DNA testing.