In the early 1980s, Werdnig and Hoffman described a disorder of progressive muscular weakness beginning in infancy that resulted in early death, though the age of death was variable. Werdnig-Hoffman disease is a rare form of spinal muscular atrophy (SMA) presenting in infants. In pathologic terms, it is an autosomal recessive condition characterized by the degeneration of anterior horn cells, leading to profound symmetrical weakness and wasting of voluntary muscle. The central role of lower motor neuron degeneration was confirmed in subsequent pathologic studies demonstrating a loss of anterior horn cells in the spinal cord and cranial nerve nuclei. In other words, Werdnig Hoffman Paralysis/Disease is a genetic disorder beginning in infancy or young childhood and is characterized by progressive atrophy of the skeletal muscle resulting from degeneration of the cells in the anterior horn of the spinal cord and the motor nuclei in the brainstem. It is also called Familial Spinal muscular atrophy (SMA), Hoffman’s atrophy, and infantile spinal muscular atrophy etc; with the most common one being Spinal Muscular Atrophy – Type I (SMA type I). This condition is transmitted as an autosomal-recessive trait and occurs more frequently in siblings. Degeneration of nerve cells within the brainstem and anterior horn cells within the spinal cord leads infected babies to muscle weakness of the truncal, and extremity muscles initially followed by chewing, swallowing and breathing difficulties.
The spinal muscular atrophies are the second most common autosomal-recessive inherited disorders after Cystic Fibrosis. The acute infantile onset SMA type I affects approximately 1 per 10000 live births with a carrier frequency of approximately 1 in 50 births. Male individuals are most frequently affected despite the autosomal recessive inheritance, especially with the early onset forms of spinal muscular atrophy, ie, SMA type I &...