$Unique_ID{BRK03739} $Pretitle{} $Title{Fiber Type Disproportion, Congenital} $Subject{Fiber Type Disproportion Congenital CFTD Myopathy of Congenital Fiber Type Disproportion Atrophy of Type I Fibers Myopathy Congenital With Fiber-Type Disproportion Batten-Turner Congenital Myopathy Becker Muscular Dystrophy Emery-Dreifuss Muscular Dystrophy Duchenne Muscular Dystrophy Myotonic Dystrophy Leyden-Moebius Muscular Dystrophy Gower's Muscular Dystrophy} $Volume{} $Log{} Copyright (C) 1989 National Organization for Rare Disorders, Inc. 713: Fiber Type Disproportion, Congenital ** IMPORTANT ** It is possible that the main title of the article (Congenital Fiber Type Disproportion) is not the name you expected. Please check the SYNONYM listing to find the alternate names and disorder subdivisions covered by this article. Synonyms CFTD Myopathy of Congenital Fiber Type Disproportion Atrophy of Type I Fibers Myopathy, Congenital, With Fiber-Type Disproportion Information on the following diseases can be found in the Related Disorders section of this report: Batten-Turner Congenital Myopathy Becker Muscular Dystrophy Emery-Dreifuss Muscular Dystrophy Duchenne Muscular Dystrophy Myotonic Dystrophy Leyden-Moebius Muscular Dystrophy Gower's Muscular Dystrophy General Discussion ** REMINDER ** The information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Congenital Fiber Type Disproportion (CFTD) is a rare genetic muscle disease that is apparent at birth. Major symptoms may include loss of muscle tone (hypotonia) and weakness, scoliosis, a drawing up of the muscles, high arched palate, dislocated hips, short stature, and deformities of the feet. Symptoms Congenital Fiber Type Disproportion (CFTD) is characterized by muscle weakness which is usually noticeable at birth. Other features may be nonprogressive loss of muscle tone, curvature of the spine (scoliosis), dislocation of the hip bones and foot deformities. Some patients with CFTD may also have involuntary movements, mental retardation, growth failure, bulging of the forehead, and abnormal hair. Sometimes only one feature of the disorder is present, and in other cases many symptoms may occur. The only way to obtain a definite diagnosis of CFTD is by muscle biopsy which shows a difference in the size of Type I and Type II muscle fibers: Type I fibers are unusually small and wasted away (atrophied). Symptoms of this disorder usually improve as the person gets older. Causes 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. 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. If one receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will show no symptoms. The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is twenty-five percent. Fifty percent of their children will be carriers, but healthy as described above. Twenty-five percent of their children will receive both normal genes, one from each parent, and will be genetically normal. Affected Population Congenital Fiber Type Disproportion affects males and females in equal numbers. The disorder is usually present at birth but may improve with advancing age. Related Disorders Symptoms of the following neuromuscular disorders can be similar to those of Congenital Fiber Type Disproportion. Comparisons may be useful for a differential diagnosis: Batten Turner Muscular Dystrophy first appears as muscle floppiness during infancy. This is followed by frequent falling and stumbling which is associated with mild muscular weakness and generalized loss of muscle tone (hypotonia). There may be a slight delay on reaching milestones or early motor development. In particular the pelvic girdle, neck and shoulder girdle may be affected. Although walking usually becomes normal later in life, there may be a residual handicap in the performance of physical activities during adulthood. (For more information on this disorder, choose "Batten- Turner" as your search term in the Rare Disease Database). Becker Muscular Dystrophy (BMD) is characterized by slowly progressive weakness of the hip and shoulder muscles. These muscles tend to be firm and rubbery. Deep tendon reflexes may be lost early in the course of this disorder. Ability to walk is affected, and mild mental retardation may be present. Joint contractures, curvature of the spine (scoliosis), restrictive lung disease, and in rare cases heart problems, can develop with time. (For more information on this disorder, choose "Becker" as your search term in the Rare Disease Database). Emery-Dreifuss Muscular Dystrophy is usually first noticed in early childhood, around the age of four or five, with the onset of slowly progressive muscle weakness in the legs causing the child to walk on the toes. Shoulder muscles eventually show a marked weakness and walking takes on a characteristic waddle. Later the neck may be involved and the spine may become rigid. Heart problems are a very prominent feature and may result in serious complications. (For more information on this disorder, choose "Emery-Dreifuss" as your search term in the Rare Disease Database). Duchenne Muscular Dystrophy starts in infancy, but visible symptoms of weakness generally do not appear before the age of two or three. Neck muscles and the large muscles of the legs and the lower trunk are the first to be affected. Over a period of several years, muscle wasting progresses to the upper trunk and the arms, eventually involving all the major muscle groups. (For more information on this disorder, choose "Duchenne" as your search term in the Rare Disease Database). Myotonic Dystrophy is an inherited disorder involving the muscles, vision, and endocrine glands. It may also cause mental deficiency and loss of hair. It usually begins during young adulthood and is marked initially by an inability to relax muscles after contraction. Loss of muscle strength, mental deficiency, cataracts, reduction of testicular function, and frontal baldness are also symptomatic of this disorder. Tripping, falling, difficulty in moving the neck, lack of facial expression and a nasal sounding voice are among many symptoms that can result from selective muscle involvement. (For more information on this disorder, choose "Myotonic" as your search term in the Rare Disease Database). Leyden-Moebius Muscular Dystrophy (Limb-Girdle Muscular Dystrophy) is a progressive disorder that usually begins during pre-adolescence. The pelvic area is the most severely affected with weakness and muscular deterioration. Muscles of the face, shoulders and arms are also affected. This disorder is inherited by a different mode of transmission than that of Becker Muscular Dystrophy. Gower's Muscular Dystrophy is a rare, slowly progressive weakness that begins in the hands and feet, then extends to other nearby areas of the body causing only moderate weakness. This disorder usually begins during adulthood. Therapies: Standard Treatment of Congenital Fiber Type Disproportion may consist of active and passive type exercises and physical therapy. Functional improvement usually occurs as the patient matures. Genetic counseling may be of benefit for patients and their families. Other treatment is symptomatic and supportive. Therapies: Investigational This disease entry is based upon medical information available through December 1989. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources For more information on Congenital Fiber Type Disproportion, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 NIH/National Institute of Neurological Disorders & Stroke (NINDS) 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5751 (800) 352-9424 Muscular Dystrophy Association, National Office 3561 E. Sunrise Dr. Tucson, AZ 85718 (602) 529-2000 For genetic information and genetic counseling referrals: March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 (914) 428-7100 Alliance of Genetic Support Groups 35 Wisconsin Circle, Suite 440 Chevy Chase, MD 20815 (800) 336-GENE (301) 652-5553 References MENDELIAN INHERITANCE IN MAN, 8th ed.: Victor A. McKusick; Johns Hopkins University Press, 1986. Pp. 1094. CLINICAL VARIABILITY IN CONGENITAL FIBER TYPE DISPROPORTION. R.R. Clancy, et al.; J Neurol Sci (June, 1980, issue 46 (3)). Pp. 257-266. CONGENITAL FIBER DISPROPORTION; ATROPHY OF TYPE I FIBERS. REPORT OF 11 CASES. J.A. Levy, et al.; Arq Neuropsiquiatr (June, 1987, issue 45 (2)). Pp. 153-158. MUSCLE FIBER TYPE TRANSFORMATION IN NEMALINE MYOPATHY AND CONGENITAL FIBER TYPE DISPROPORTION. T. Miike, et al.; Brain Dev (1986, issue 8 (5)). Pp. 526-632.