Myotonic Dystrophy Explained: A Genetic Condition We Specialise in Diagnosing
As part of a group of inherited disorders known as muscular dystrophies, myotonic dystrophy is the most common form that begins in adulthood. It is characterized by progressive muscle-weakening and wasting and it is a genetic condition, frequently overlooked, that we specialise in diagnosing.
Classical clinical signs of the condition are weakness, with an inability to relax muscles after they’re used, with prolonged contractions also common. This is most noteworthy in the hand muscles. For instance, it could be that a person might open a door and find it difficult to let go of a door handle or experience slurring of speech due to a temporary locking of their jaw.
Other symptoms and signs of myotonic dystrophy include:
Early-onset cataracts or clouding of the eye’s lens
Cardiac conduction defects (Heartbeat electrical signal abnormalities)
Diabetes mellitus (high blood sugar)
These symptoms often appear during a person’s 20s or 30s, although the condition can develop at any age. In terms of severity, the condition can vary significantly, even when experienced by members of the same family. The most damaging form of the condition is known as the congenital form, when it often impacts upon the pregnancy and signs are present at the birth of an affected patient.
Two Types of Myotonic Dystrophy
People will usually get one of two main varieties of the condition; type 1 & type 2. There are shared symptoms between the two, but their causes are different. Type 1 - typically the milder form - is caused by a DMPK gene mutation and Type 2 involves a mutation of the CNBP gene.
Type 1 muscle weakness tends to affect the distal muscles (those further away from the body’s centre) in areas like the face, hands and lower legs. It can be further subdivided into two categories; congenital and mild, with the former often apparent at birth and the latter appearing in mid to late adulthood.
Type 2 muscle weakness primarily affects the proximal muscles (those closest to the body’s centre) in areas like the neck, elbows, shoulders and hips.
Both types of myotonic dystrophy are caused by a short DNA segment becoming abnormally repeated multiple times. This then creates an unstable area within the gene, leading to the symptoms mentioned previously.
Experts in the Diagnosis of Myotonic Dystrophy
Dr Reardon was one of the team in Cardiff who identified the gene for this disorder in 1992 and
has seen hundreds of affected families. The diagnostic test, in routine use all over the world, is
based on the discovery he and the Cardiff team made 30 years ago.
Our clinic specialises in the diagnosis of myotonic dystrophy, so you get the peace of mind that you’re in very good and highly experienced hands. Working with professionalism and the utmost care at all times, we’re committed to meeting the highest clinical standards and making the whole process as stress-free as possible.
If you’d like to know more about us and the complete range of genetic testing we offer, visit us at www.genetics.ie. Alternatively, to speak to us directly about your needs, call us on 01 206 4329 and a member of our team will be glad to assist.