Presently it is best to regard disproportion in muscle fiber size with 1 fiber smallness, or hypotrophy, as a pathological pattern that can occur in congenital myopathies and also in many other conditions. It is a rare muscle disease that is apparent at birth. Multiple joint contractures are also frequent. The weakness is diffuse, but pharyngeal and ocular muscles are spared. The tendon reflexes are hypoactive or absent.
Mental development is normal.
The prognosis is relatively favorable in most patients. However, there are cases in which the same histological features are associated with slowly progressive weakness from childhood, rigid spine syndrome, or severe and progressive motor involvement with kyphoscoliosis and respiratory insufficiency. Based upon medical information from the book Myopathies by Engle and published by McGraw Hill in 1994 Causes Human Traits, including the classic genetic diseases, are the product of the interaction of the two genes, one from the father and the other from the mother. CFTD is inherited as an autosomal recessive trait. In recessive disorders, the condition does not appear unless a person inherits the same defective gene for the same trait from each parent.