All types of muscular dystrophy are hereditary. The generesponsible for Duchenne and Becker dystrophy is transmittedthrough the mother's X chromosome. Women have two Xchromosomes, while males have one X chromosome and one Y chromosome The disease is said not to female infants as a normal gene on one X chromosome is dominant over the defective geneon chromosome X. In the other hand, women can transmit the disease in male newborns. Because boys do not inherit only one Xchromosome, they do not receive a normal gene to a counter onthe damage so that the defect occurs on chromosome X and thedisease was declared.
Dystrophin is a protein produced by muscle that helps muscle cellskeep their shape. Defective gene that lies at the origin ofDuchenne muscular dystrophy prevents the production ofdystrophin, resulting in membrane damage and necrosis (death) of muscle fibers.
Women vector (carrier) is 50% risk of transmitting disease sons.
Myotonic dystrophy is an autosomal dominant transmission. If one parent carries the gene for myotonic dystrophy, is 50% risk of transmitting the disease to children.
Other types of muscular dystrophy affecting both sexes equally.
Monday, May 30, 2011
Facio-scapular-humeral dystrophy
Facio-scapular-humeral dystrophy (or Landouzy-Dejerinedystrophy) is a hereditary disease with autosomal dominanttransmission, characterized by affecting the facial muscles and the scapular girdle (pectoral muscle, trapezius).
Facio-scapular-humeral dystrophy occurs in both sexes and oftenaffects several members of the same family.
Onset of disease is between 7 and 40 years, mostly before 20years. There is an infantile form of disease onset 1 to 2 years,rapidly progressive. Begins in adolescence classical form, is a slow and affects the facial muscles, arms and shoulders. The patient can not make gestures with facial muscles (foul), is having difficulty raising the arms and eyes closed. Life expectancy isnormal, and disability occurs relatively late.
Diagnosis is based on clinical data, age of onset, family historyand confirmed by DNA tests.
Treatment facio-scapular-humeral dystrophy consist ofphysiotherapy.
Facio-scapular-humeral dystrophy occurs in both sexes and oftenaffects several members of the same family.
Onset of disease is between 7 and 40 years, mostly before 20years. There is an infantile form of disease onset 1 to 2 years,rapidly progressive. Begins in adolescence classical form, is a slow and affects the facial muscles, arms and shoulders. The patient can not make gestures with facial muscles (foul), is having difficulty raising the arms and eyes closed. Life expectancy isnormal, and disability occurs relatively late.
Diagnosis is based on clinical data, age of onset, family historyand confirmed by DNA tests.
Treatment facio-scapular-humeral dystrophy consist ofphysiotherapy.
Myotonic dystrophy
Myotonic dystrophy is the most common form of musculardystrophy in adults, affecting approximately 30/100 000 livebabies). Transmission is autosomal dominant with variablepenetrance. Both sexes are equally affected.
The onset of signs and symptoms occurs in adolescence or later,young adults and consist in myotonic (abnormal slowness ofmuscle relaxation after contraction), weakness, amiotrofii distal(limb muscle atrophy, especially of the hand) and cardiomyopathy(damage heart muscle).
Myotonic dystrophy may be accompanied by cataracts, frontalbalding in particular, mental retardation and hormonal disorders(disorders of virility, testicular atrophy in men, menstrual disorders,recurrent miscarriage in women).
The onset of signs and symptoms occurs in adolescence or later,young adults and consist in myotonic (abnormal slowness ofmuscle relaxation after contraction), weakness, amiotrofii distal(limb muscle atrophy, especially of the hand) and cardiomyopathy(damage heart muscle).
Myotonic dystrophy may be accompanied by cataracts, frontalbalding in particular, mental retardation and hormonal disorders(disorders of virility, testicular atrophy in men, menstrual disorders,recurrent miscarriage in women).
Becker muscular dystrophy
Becker muscular dystrophy (DMB) is also a hereditary disease,with the same cormosomul X linked recessive transmission, butwith slower growth and a more benign clinical picture than withDuchenne muscular dystrophy. Protein called dystrophin, the absence in Duchenne's disease, is found in insufficient quantities,and only partially fulfilling the function (to protect the membrane thatwraps the muscle fibers).
Becker muscular dystrophy symptoms are generally lesspronounced than those of Duchenne myopathy. Their onset isvariable, from 2-45 years, mean age of occurrence of symptoms is12 years. Walking ability is preserved after the age of 16 years,and deformation of the spine is less common. Respiratory failure isnot observed before 40 -50 years. Intellectual functions are notaltered. Touching heart is less severe than Duchenne myopathy.
Becker muscular dystrophy is 10 times rarer than Duchennedisease, affecting about three in 10,000 boys. Most people live to50 -60 years, causes of death are the same as with Duchennemyopathy: lung infections and heart failure.
Becker muscular dystrophy symptoms are generally lesspronounced than those of Duchenne myopathy. Their onset isvariable, from 2-45 years, mean age of occurrence of symptoms is12 years. Walking ability is preserved after the age of 16 years,and deformation of the spine is less common. Respiratory failure isnot observed before 40 -50 years. Intellectual functions are notaltered. Touching heart is less severe than Duchenne myopathy.
Becker muscular dystrophy is 10 times rarer than Duchennedisease, affecting about three in 10,000 boys. Most people live to50 -60 years, causes of death are the same as with Duchennemyopathy: lung infections and heart failure.
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