Última actualización:
May 23, 2008
Años publicados: 1986, 1989, 1990, 1993, 1994, 1996, 1997, 2003
Machado-Joseph Disease (MJD-III), also called spinocerebellar ataxia type III, is a rare, inherited, ataxia (lack of muscular control) affecting the central nervous system and characterized by the slow degeneration of particular areas of the brain called the hindbrain. Patients with MJD may eventually become crippled and/or paralyzed but their intellect remains intact. The onset of symptoms of MJD varies from early teens to late adulthood.
Three forms of Machado-Joseph Disease are recognized: Types MJD-I, MJD-II, and MJD-III. The differences in the types of MJD relate to the age of onset and severity. Earlier onset usually produces more severe symptoms.
The symptoms of MJD Type I present between the ages of 10 and 30 years and progress rapidly. They may include severe weakness in the arms and legs (dystonia), spasticity or muscle rigidity, (hypertonia), awkward body movements (ataxia) often involving a slow, staggering, lurching gait (athetosis) that may be mistaken for drunkenness, slurred speech and swallowing (dysarthria), and possible damage to the muscles that control eye movements (ophthalmoplegia) and bulging eyes (exophthalmia). Mental alertness and intellectual capacities are unaffected.
MJD-Type II symptoms are similar to those of Type I, but the disease progresses at a slower rate. Onset of Type II disease is usually between 20 and 50 years of age. The distinctive characteristic of Type II is increased dysfunction of the cerebellum that results in an unsteady gait (ataxia) and difficulty coordinating movements of the arms and legs, as well as spastic muscle movements.
MJD-Type III presents later in life, between years 40 and 70, and is characterized by an unsteady gait (ataxia) and is distinguished from the other forms of this disease by loss of muscle mass (amyotrophy) due to inflammation and degeneration of the peripheral nerves (motor polyneuropathy). Loss of feeling, lack of sensitivity to pain, abnormal sensations, impaired ability to coordinate movement of the arms and legs, and diabetes are also common. The progression of Type III disease is slowest of the three types.
A number of the symptoms, and their appearance in combination, resemble the symptoms of other neurologic disorders such as Parkinson’s disease or multiple sclerosis. A proper diagnosis is therefore difficult and should be the responsibility of an experienced neurologist.
The gene responsible for MJD has been identified and mapped to Gene Map Locus; 14q24.3-q31. This gene is associated with an abnormal number of CAG trinucleotide repeats (sometimes called triplets) in the DNA. (CAG refers to the Cytosine-Adenine-Guanine trinucleotide structure.) «Normal» DNA usually has between 12 and 43 copies of the CAG trinucleotide. In persons with the disease, the DNA contains from 56-86 copies of this trinucleotide. Severity of symptoms and age of onset are related directly to the number of the repeats. Thus, MJD-I will have fewer of these triplets while MJD-III will have the greater number. The number of the CAG triplets found in the DNA of patients with MJD-II lies between the two extremes.
MJD is inherited as an autosomal dominant trait. Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22 and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated «p» and a long arm designated «q». Chromosomes are further sub-divided into many bands that are numbered. For example, «chromosome 11p13» refers to band 13 on the short arm of chromosome 11. The numbered bands specify the location of the thousands of genes that are present on each chromosome.
Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosomes received from the father and the mother.
Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.
MJD is a rare inherited neurological disorder that disproportionately affects individuals of Portuguese descent, especially those from the Azores, an island colonized by Portuguese people. MJD appears to affect slightly more males than females.
While a family history and physical examination help in the diagnosis, the gold standard of diagnostic tests that detects 100% of the cases is the direct determination of the number of suspect CAG triplets in a patient's DNA. This may be readily done at a specialized genetic clinical laboratory.
Treatment
Treatment is symptomatic and supportive. The drugs L- dopa and baclofen may relieve muscle rigidity and spasticity. Individuals with at least one family member who has been diagnosed with this disease should consider genetic counseling.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
For information about clinical trials sponsored by private sources, contact:
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TEXTBOOKS
Chang T, Pearl PL. Machado-Joseph Disease. In: NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:555.
Beers MH, Berkow R., eds. The Merck Manual, 17th ed. Whitehouse Station, NJ: Merck Research Laboratories; 1999:1472.
Adams RD, Victor M, Ropper AA. Eds. Principles of Neurology. 6th ed. McGraw-Hill Companies. New York, NY; 1997:1087.
REVIEW ARTICLES
Cummings CJ, Zoghbi HY. Trinucleotide repeats: mechanisms and pathophysiology. Annu Rev Genomics Hum Genet. 2000;1:281-328.
Evidente VG, Gwinn-Hardy KA, Caviness JN, et al. Hereditary ataxias. Myo Clin Proc. 2000;75:475-90.
Koeppen AH. The hereditary ataxias. J Neuropathol Exp Neurol. 1998;57:531-43.
JOURNAL ARTICLES
Subramony SH, Hernandez D, Adams A, et al. Ethnic differences in the expression of neurodegenerative disease: Machado-Joseph disease in Africans and Caucasians. Mov Disord. 2002;17:1068-71.
Garcia Ruiz PJ, Mayo D, Hernandez J, et al. Movement disorders in hereditary ataxias. J Neurol Sci. 2002;15:59-64.
Munoz E, Rey MJ, Mila M, et al. Intranuclear inclusions, neuronal loss and CAG mosaicism in two patients with Machado-Joseph disease. J Neurol Sci. 2002;15:19-25.
Lee Y, Oh MR, Kim CH, et al. A simple method for the detection of neurologic disorders associated with CAG repeat expansion using PCR-microtiter plate hybridization. J Biotechnol. 2002;95:215-23.
Isozaki E, Naito R, Kanda T, et al. Different mechanisms for vocal cord paralysis between spinocerebellar ataxia (SCA-1 and SCA-3) and multiple system atrophy. J Neurol Sci. 2002;197:37-43.
Fukutake T, Shinotoh H, Nishino H, et al. Homozygous Machado-Joseph disease presenting as REM sleep behaviour disorder and prominent psychiatric symptoms. Eur J Neurol. 2002;9:97-100.
Maciel P, Costa MC, Ferro A, et al. Improvement in the molecular diagnosis of Machado-Joseph Disease. Arch Neurol. 2001;58:1821-27.
van Alfen M, Simke RJ, Zwarts MJ, et al. Intermediate CAG repeat lengths (53, 54) for MJD/SCA3 are associated with an abnormal phenotype. Ann Neurol. 2001;49:805-07.
FROM THE INTERNET
McKusick VA, Ed. Online Mendelian Inheritance in Man (OMIM). The Johns Hopkins University. Entry Number; 109150: Last Edit Date; 12/26/2002.
McKusick VA, Ed. Online Mendelian Inheritance in Man (OMIM). The Johns Hopkins University. Entry Number; 607047: Last Edit Date; 12/16/2002.
Subramony SH, McDaniel DO, Smith SC, et al. Spinocerebellar Ataxia Type 3. GENEReviews. Last Update; 24 May 2001:12 pp.
www.geneclinics.org/servlet/access?id8888891&key=ou2
GPnotebook. spinocerebellar ataxia type 3. nd. 3pp.
www.gpnotebook.co.uk/cache/-294977481.htm
Trinucleotide Repeat Disorders. Part 6: Polyglutamine Diseases. Last modified: 9-13-02. 2pp.
www.stanford.edu/group/hopes/rltdsci/trinuc/f6.html
Machado/Joseph’s Disease Information. nd. 4pp.
www.lusaweb.com/machado.htm
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Aprende más https://rarediseases.org/patient-assistance-programs/caregiver-respite/The information provided on this page is for informational purposes only. The National Organization for Rare Disorders (NORD) does not endorse the information presented. The content has been gathered in partnership with the MONDO Disease Ontology. Please consult with a healthcare professional for medical advice and treatment.
The Genetic and Rare Diseases Information Center (GARD) has information and resources for patients, caregivers, and families that may be helpful before and after diagnosis of this condition. GARD is a program of the National Center for Advancing Translational Sciences (NCATS), part of the National Institutes of Health (NIH).
View reportOrphanet has a summary about this condition that may include information on the diagnosis, care, and treatment as well as other resources. Some of the information and resources are available in languages other than English. The summary may include medical terms, so we encourage you to share and discuss this information with your doctor. Orphanet is the French National Institute for Health and Medical Research and the Health Programme of the European Union.
View reportOnline Mendelian Inheritance In Man (OMIM) has a summary of published research about this condition and includes references from the medical literature. The summary contains medical and scientific terms, so we encourage you to share and discuss this information with your doctor. OMIM is authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine.
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