Myotonic dystrophy

Py : Jehad abdullah ali

To find out what is the Muscular Dystrophy

To find out what is the Myotonic dystrophy

To learn symptoms of Myotonic dystrophy

To be know how to manage the Myotonic

dystrophy

Muscular Dystrophy

a group of hereditary progressive diseases.

Muscular Dystrophy affects muscular

strength and action

Muscle FibersMuscles are made of bundles of

fiber (cells). A group of

independent proteins along the

membrane surrounding each fiber

helps to keep muscle cells working

properly.

When one of these proteins,

dystrophin, is absent the result is

MD

Myotonic dystrophy

introduction

Myotonic dystrophy is part of a group of

inherited disorders called muscular dystrophies.

It is the most common form of muscular

dystrophy that begins in adulthood.

Myotonic dystrophy is an inherited disorder of

muscle function.

There are two major types of myotonic

dystrophy: type 1 and type 2

How common is myotonic dystrophy?

affects at least 1 in 8,000 people worldwide.

The prevalence of the two types of myotonic

dystrophy varies among different geographic

and ethnic populations.

In most populations, type 1 appears to be more

common than type 2. However, recent studies

suggest that type 2 may be as common as type

1 among people in Germany and Finland.

SYMPTOMS OF MYOTONIC

DYSTROPHY

The symptoms of myotonic dystrophy vary

greatly from person to person

1-Myotonia

Delayed relaxation of a muscle after an

initial contraction.

Myotonia is most evident in the hands, and

results in difficulty releasing grip and a

feeling of muscle stiffness

Myotonia can be diagnosed by an

electromyogram (EMG)

2- Muscle weakness

The muscles of the face are often the first

to show weakness, resulting in a lack of

facial expression or mask-like appearance

of the face (myotonic facies)

slurred speech (dysarthria)

droopy eyelids

mask-like appearance of the face

(myotonic facies) with droopy

eyelids

Muscle weakness cont’

The muscles of the lower leg, ankle, foot,

forearm and hand are usually the next

group of muscles to show weakness.

This lead to difficulty with walking, and

with finger and hand movements.

The muscles involved with breathing and

swallowing may become weak over time

3- cloudiness of the lens of the eye

The majority of persons with myotonic

dystrophy will eventually develop cataracts

(cloudiness of the lens of the eye) that cause

vision to become blurry. Cataracts are often

the first recognized sign of DM. They can

occur in persons without DM, especially in the

elderly. In DM however, cataracts develop at a

younger age, usually in the forties or fifties.

Cataracts are treatable through surgery

cataracts

4- Abnormalities of heart rhythm (arrhythmia)

*Other symptoms seen in some but not all

persons with DM

DM described

DM is described as being mild, classical or

congenital based on the severity and age of

onset of symptoms-At this time, there is no

treatment or cure that can prevent the

symptoms of myotonic dystrophy-

SYMPTOMS OF MAYOTONIC

Dystrophy Type 2

The symptoms of DM2 are very similar to

those of DM, and both conditions are

inherited in the same way. The main

difference between them is at the genetic

level. The genetic change that causes DM2

is different from DM

INHERITANCE OF DM

DM is inherited in an autosomal dominant

pattern

DM is caused by a change or mutation in a

specific gene, called the myotonic

dystrophy protein kinase (DMPK) gene,

which is essential for normal muscle and

body function.

Every person has 23 pairs of chromosomes,

which contain two copies of each gene. The

DMPK gene is gif myotonic dystrophy

protein kinase and located on chromosome

number 19.

The DMPK gene is located on the long (q) arm of chromosome 19 at position

13.3.

More precisely, the DMPK gene is located from base pair 45,769,708 to base

pair 45,782,556 on chromosome 19.

The genetic change that causes DM is

called a CTG repeat expansion

CTG represents a specific pattern of

DNA.

It is normal to have between 5 to 37 CTG

repeats in both copies of the DMPK gene.

DM2 is also inherited in an autosomal

dominant pattern. The gene for DM2 is CNBP

(also known as ZNF9) gif nucleic acid

binding protein , localized to chromosome

number 3.

The CNBP gene is located on the long (q) arm of chromosome 3 at

position 21.

More precisely, the CNBP gene is located from base pair 129,167,814 to

base pair 129,183,966 on chromosome 3

Non-molecular testing

Electromyography (EMG). A needle

electrode placed in the muscle of an

affected adult records myotonic discharges

Serum CK concentration. Serum CK

concentration may be mildly elevated in

individuals with DM1 with weakness, but

is normal in asymptomatic individuals.

Molecular Genetic Testing

Molecular genetic testing detects mutations

in nearly 100% of affected individuals.

Management

1. Treatment of manifestations

management of pain

consultation with a cardiologist for symptoms

or ECG evidence of arrhythmia

2. Surveillance

eye examination every two years

attention to nutritional status