( Return to Lesions Front Page )

A woman with two prior pregnancies reported that the fetal movements of her third baby were less vigorous than previous fetuses. At birth the baby was weak and limp, the cry and sucking movements feeble, and respiratory movements ineffective. The baby died at 6 months.

Neurologic examination showed the baby was hypotonic and weak. Muscle fasciculations were present but not visible, except for those of the tongue, because of the covering adipose tissue. Tendon reflexes were absent but normal sensory responses to pain, temperature, and touch were present.

Explanation -

The anterior horn cells in the spinal cord and major motor nuclei of the brainstem are degenerative, dying, and reduced in number. Other systems of neurons are not affected.

This is a form of infantile, hereditary, progressive, non-myopathic muscular atrophy due to death of the anterior horn cells. An adult form of this hereditary muscular atrophy, which simulates muscular dystrophy but is due to death of anterior horn cells, is the Kugelberg-Welander syndrome.