What is BMD

Becker Muscular Dystrophy (BMD) is a slow progressive disease that predominantly affects male and is very similar, although milder, to Duchenne Muscular Dystrophy. It is characterized by slowly progressive muscle weakness of the legs and Pelvis Although the loss of muscle cells is visibly shown by the reduction in size of these muscles the size of certain muscles, such as the calves may appear to increase as the muscle fibres are replaced by fat and connective tissue. Becker and Kiener initially described Becker muscular dystrophy (BMD) (also known as Benign pseudohypertrophic Muscular Dystrophy )in 1956 thus giving the condition its name.

What are the symptoms ? The average age at diagnosis in Becker muscular dystrophy is 11 years but the range is very wide – sometimes the diagnosis may be made in early childhood or well into adult life. Symptoms usually begin very mildly in childhood; often cramps on exercise are the only problem at first but a few affected boys  may have difficulty in learning how to walk as a toddler.  Later symptoms include difficulty in walking, running, climbing stairs and lifting heavy objects.

A typical developmental history of a patient with BMD may include the following:

  • Delayed gross motor milestones (eg, late walking, running, jumping, difficulty with stair climbing) may be reported.
  • Initially, some children who are later diagnosed with BMD may be called clumsy.
  • Increasing numbers of falls, toe walking, and difficulty rising from the floor may be later features.
  • Use of Gowers Maneuver or a modified  form to get up from floor. –See Youtube examples.
  • Calf muscles initially enlarge (an attempt by the body to compensate for loss of muscle strength), but the enlarged muscle tissue is eventually replaced by fat and  connective tissue (pseudohypertrophy) as the legs become less used.
  • Proximal muscle weakness is reported.
  • Subclinical cases may manifest later in life; dilated cardiomyopathy can be the first sign of BMD.
  • Elevated CPK (creatine phosphokinase) levels in blood: Elevated CK levels are more common at younger ages and decreases later in life
  • Elbow contractures may be seen later in life.
  • Cardiomyopathy (damage to the heart) does not occur as commonly with this Becker as it does with Duchenne’s muscular dystrophy but is a possible symptom .
  What causes it
Genes hold the information to build and maintain an organism's cells  -Wikipedia, the free encyclopedia

A fault in a particular gene (dystrophin) carried on the X chromosome leads to the formation of a faulty protein in muscle fibres. This protein, also called dystrophin, is absent or severely abnormal in Duchenne MD. In Becker MD a milder fault makes the dystrophin molecule smaller (or occasionally larger) or less abundant than normal. When dystrophin is abnormal the muscle fibres gradually break down and the muscles slowly become weaker.  This information was found on the Muscular Dystrophy’s site where a more detailed explanation may be found

The disorder is inherited with an X-linked recessive inheritance pattern — the gene is located on the X chromosome.Since women have two X chromosomes, if one X chromosome has the defective gene, the second X chromosome will have a working copy of the gene to compensate. In these cases, some women have much milder symptoms because of this ability to compensate.Men have an X and a Y and because they don’t have another X to compensate for the defective gene, they will develop symptoms if they inherit the defective gene.
Further Information can be found on The Muscular Dystrophy Campaigns website http://www.muscular-dystrophy.org/about_muscular_dystrophy/conditions/94_becker_muscular_dystrophy

or from the MDAs website

 

 

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