Information on the following diseases can be found in the Related Disorders section of this report:

• Congenital Benign Hypotonia
• Werdnig-Hoffman Disease
• Canavan's Leukodystrophy
• Hypotonia (General)

The first symptoms of Batten Turner Type Congenital Myopathy in a newborn are the slow, progressive loss of muscle tone characterized by floppiness (hypotonia) and general weakness. Early motor skills and other important developmental milestones may be slightly delayed. Toddlers with this disorder usually have mild muscle weakness and may be prone to falling or stumbling. The muscles of the pelvis, neck, and shoulder area are most commonly affected. Since the symptoms of this disease are not progressive during adulthood, most people with Batten Turner Type Congenital Myopathy walk normally as adults. However, some physical activities may be slightly impaired.

Batten Turner Type Congenital Myopathy is inherited as an autosomal recessive genetic trait. Human traits, including the classic genetic diseases, are the product of the interaction of two genes, one received from the father and one from the mother. In recessive disorders, the condition does not appear unless a person inherits the same defective gene for the same trait from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is 25 percent. Fifty percent of their children risk being carriers of the disease, but generally will not show symptoms of the disorder. Twenty-five percent of their children may receive both normal genes, one from each parent, and will be genetically normal (for that particular trait). The risk is the same for each pregnancy.

Batten Turner Type Congenital Myopathy is an extremely rare disorder that affects males and females in equal numbers. The symptoms of this disorder are most obvious during infancy and childhood. Nine cases of Batten Turner Type Congenital Myopathy have been described in the medical literature. Six of these cases were reported in one family.

Symptoms of the following disorders can be similar to those of Batten Turner Type Congenital Myopathy. Comparisons may be useful for a differential diagnosis:

Congenital Hypotonia is a nonprogressive neuromuscular disorder which is present at birth. This condition is characterized by decreased muscle tone or floppiness with no known cause or may be a symptom of another disorder. Newborns with this disorder have muscle weakness and generalized weakness. In many cases the symptoms improve as the child ages. (For more information on this disorder, choose "Hypotonia" as your search term in the Rare Disease Database.)

Werdnig-Hoffmann Disease is a rare inherited neuromuscular disorder of childhood characterized by generalized muscle weakness and the progressive loss of muscle mass (atrophy). Symptoms may also include hypermobility of the joints, absent tendon reflexes, and rapid twitching (fasciculations) of the tongue. Werdnig-Hoffman Disease is a progressive disorder and affected children may develop breathing problems or kidney impairment. (For more information on this disorder, choose "Werdnig-Hoffman" as your search term in the Rare Disease Database.)

Canavan's Leukodystrophy is a rare inherited disorder that is characterized by the progressive degeneration of the central nervous system. The early symptoms of this disorder include a general lack of energy, floppiness, and the loss of previously acquired motor skills. Symptoms appear in early infancy and are rapidly progressive. Other symptoms may include jerky motions of the arms and legs, poor head control, and/or hearing loss. (For more information on this disorder, choose "Canavan's Leukodystrophy" as your search term in the Rare Disease Database.)

Congenital Hypotonia may occur in association with many other disorders. Generalized muscle weakness and floppiness may be symptoms of these disorders. A variety of other symptoms or unusual facial or physical characteristics may also occur. These other disorders include, but are not limited to, Congenital Hypomyelination Neuropathy, Aicardi Syndrome, Cri du Chat Syndrome, Multiple Carboxylase Deficiency, De Barsy Syndrome, Down's Syndrome, FG Syndrome, Neonatal Herpes, Non-Ketotic Hyperglycinemia, and Tay- Sachs Disease. For a listing of diseases associated with muscle weakness in newborn children and information on these disorders, choose "Hypotonia" as your search term in the Rare Disease Database.)

Adults with Batten Turner Type Congenital Myopathy should be encouraged to get adequate exercise and to avoid obesity. Affected adults may experience episodes of mild muscle weakness, but generally there are no major physical disabilities.

Research on genetic disorders and their causes is ongoing. The National Institutes of Health (NIH) is sponsoring the Human Genome Project which is aimed at mapping every gene in the human body and learning why they sometimes malfunction. It is hoped that this new knowledge will lead to prevention and treatment of genetic disorders in the future.

McKusick VA, ed. Online Mendelian Inheritance In Man (OMIM). The Johns Hopkins University. Myopathy, Congenital. Entry Number; 255300: Last Edit Date; 3/18/2004.

TEXTBOOKS
Adams RD, Victor M., eds. Principles of Neurology. 5th Edition. McGraw Hill Co., NY. 1993:1248.

Wyngaarden JB, Smith LH Jr., eds. Cecil Textbook of Medicine. 19th Edition. W.B. Saunders Co., Philadelphia, PA; 1992:2256.

Magalini SI, Magalini SC, De Francisci,, eds. Dictionary of Medical Syndromes. 3rd Edition. J.B. Lippincott Co., Philadelphia, PA. 1990:78.

JOURNAL ARTICLES
Batten FE. Three cases of myopathy, infantile type. Brain. 1903;26:147-48.

Batten FE. The myopathies or muscular dystrophies: a critical review. Quart J Med. 1910;3:313-28.

Turner JWA. On myotonia congenita. Brain. 1949;72:25-34.

Turner JWA, Lees F. Congenital Myopathy/a fifty-year follow-up. Brain. 1962;85:733-40.

Zellweger H, Afifi A, McCormick WF, et al. Benign congenital muscular dystrophy: a special form of congenital hypotonia. Clin Pediatr (Phila). 1967;6:655-63.