Hi everyone;

The following is a "preview" of a new pamphlet on distal MD being
prepared by the US MDA. This was sent to me by Sharon Hesterlee, who
invites comments on any points that may need clarification.

********
Hi Brad,

I'm in the process of editing and rewriting some parts of our new
"Rare Dystrophies" pamphlet, which includes the distal muscular
dystrophies. I wonder if you would be willing to take a look at my
information (posted at the end of this message) and give me some
feedback. Also, did you say you started an email list for distal MD?
If so, please feel free to post it there as well. People are welcome
to email me directly with comments.

Thanks!

Sharon

Sharon E. Hesterlee, Ph.D.
Director of Research Development
Muscular Dystrophy Association
3300 E. Sunrise Drive
Tucson, Arizona 85718

shesterlee@...
Phone: 520- 529-5433
Fax: 520- 529-5454


Distal Muscular Dystrophy

First described in 1902, distal muscular dystrophy is the name of a
group of disorders that primarily affect distal muscles--those muscles
that are farthest away from the trunk of the body such as those in the
hands, feet lower arms or lower legs. Although muscle weakness is
usually first detected in the distal muscles, with time, other muscle
groups may become affected as well. Intellect and fertility are not
affected in these diseases.

The distal muscular dystrophies are caused by many different genetic
defects, not all of which are currently known. Also, some of the
distal muscular dystrophies that appear to have different symptoms and
have been given different names based on these symptoms, may actually
be caused by defects in the same gene.

Your own form of distal muscular dystrophy may or may not fit into one
of these categories. Many of these diseases can vary from one person
to the next and, in some cases, researchers are still in the process
of sorting out what symptoms are linked to a particular genetic
defect.

What are the types of distal muscular dystrophy?

Welander's distal myopathy: This form of distal muscular dystrophy
follows a dominant pattern of inheritance and usually has a late onset
at between 40-50 years. Upper extremities tend to be affected first,
then lower. The degree of muscle weakness involved can range from
benign to severe. Although its cause isn't yet known, the disorder
may be linked to the dysferlin gene--the same gene that's defective in
Miyoshi myopathy and limb-girdle muscular dystrophy 2B.

Finnish/Markesbery distal myopathy: Markesbery muscular dystrophy
follows a dominant pattern of inheritance with weakness starting after
age 40 in the lower extremities and progressing slowly to the upper
extremities and trunk muscles. Cardiac problems can be a feature.
Finnish muscular dystrophy (also called "tibial" muscular dystrophy),
can be severe or benign and typically affects only people of Finnish
descent. Those with only one defective gene experience mild weakness
of the tibial leg muscles later than age 40. Those with two defective
genes experience progressive weakness starting in childhood and may
lose the ability to walk by age 30. Finnish distal myopathy and
Markesbery distal myopathy are linked to the same region of chromosome
2 and may be caused by defects in the same gene.

Miyoshi distal myopathy: This disorder is inherited in a recessive
manner and involves weakness in the lower extremities, especially in
the gastrocnemius muscle. Symptoms usually begin between 15 and 30
years of age. The genetic defect that causes Miyoshi myopathy has
been mapped to the gene for a protein of unknown function called
"dysferlin." Defects in the dysferlin gene can also cause limb-girdle
muscular dystrophy 2B, which has a completely different pattern of
muscle weakness. People with the exact same genetic defect in their
dysferlin gene can have either disease, and it isn't known what
determines which pattern of symptoms a person gets.

Nonaka distal myopathy: Usually found in families of Japanese
descent, this form of distal muscular dystrophy is inherited in
recessive manner and symptoms begin between ages 20 and 40. The
anterior lower leg muscles (those in the front of the leg) are
typically affected first, but the disease may progress to affect upper
arm and leg muscles and neck muscles. The quadriceps muscles tend to
remain strong. The disease has been linked to chromosome 9 and may be
caused by a defect in the same gene that causes a different disease,
recessive hereditary inclusion body myositis.

Gower's distal myopathy: This disorder is inherited in a dominant
fashion and has its onset from childhood to 25 years of age. Weakness
is first seen in the leg and neck muscles and progresses slowly to
include upper leg muscles, hands and more neck muscles. The disorder
has been linked to chromosome 14.

Hereditary inclusion body myositis (HIBM): This disorder can be
inherited either as a dominant or a recessive disease. Onset of the
recessive form is in the 2nd or 3rd decade and muscle weakness appears
in the distal muscles (those farthest away from the trunk) and in the
proximal muscles (those nearest the trunk). The dominant form has its
onset at 25 to 40 years and weakness occurs in the distal and proximal
limb muscles with slow progression. In both forms of HIBM the muscle
tissue, as seen in thin cross sections, is characterized by the
presence of tiny protein-rimmed holes called "vacuoles."

Distal myopathy with vocal cord and pharyngeal weakness: This disorder
is inherited in a dominant manner and has been linked to chromosome 5
in the same region as the gene that's defective in limb-girdle
muscular dystrophy type 1A. Symptoms first appear between 35 and 57
years of age and include weakness of the hands, legs or voice.
Difficulty in swallowing, "dysphagia," may be a feature (see "problems
and solutions" under OPMD, p. , for more information on dysphagia).

Problems and solutions in Distal Muscular Dystrophies:

Lower limb weakness: Weakness of the lower limb muscles may make
walking or standing from a sitting position difficult. In some cases,
a type of brace called an "orthosis" that is worn over the shoe and
lower or upper leg can help with leg weakness. Eventually, a
wheelchair may be needed for
traveling long distances.

Arm weakness: Your MDA clinic can refer you to an "occupational
therapist" who will help you get the most out of your arm muscles in
performing day-to-day activities. Often, the occupational therapist
can recommend specific devices that may augment grip strength or help
you elevate your arms to better perform activities such as brushing
your teeth or hair.