Charcot-Marie-Tooth disease (CMT)

Charcot-Marie-Tooth disease (CMT) is a genetic disorder characterised by slowly progressive muscular weakness. The onset of the condition may be from childhood to late middle or old age, but most frequently is first apparent in childhood.

Also known as: Hereditary Motor and Sensory Neuropathy; Peroneal Muscular Atrophy

In this article

What are the symptoms of CMT?

Onset is in the lower limbs first, causing weakness around the ankles and, often, an abnormality in the shape of the feet (high in-step, which doctors call ‘pes cavus’). After many years, weakness may develop in the hands and spread upwards in the lower limbs to affect the knees and thighs. Mild loss of sensation may be present in the feet and hands.

What are the causes of CMT?

The underlying cause of Charcot-Marie-Tooth disease is an abnormality (called a mutation) in one of the genes responsible for producing a protein that is essential for normal nerve function. Each nerve is made up of many thousands of proteins. CMT can be caused by mutations in any one of about 30 genes – although each protein that is affected is different the end result is a similar in terms of the overall symptoms experienced by an individual with CMT.

How is CMT diagnosed?

The most common form (called type 1A), which accounts for about 70 per cent of all CMT patients, affects a protein called PMP22 and can be diagnosed by a blood test looking at the gene responsible for producing that protein. But for other forms it is more complicated. The basic diagnosis of CMT can be made by electrical tests known as ‘nerve conduction studies’.

To define the specific genetic abnormality responsible for CMT requires blood tests to look at the DNA, but at present that is only available for a small number of the responsible genes.

Whilst there are advantages in knowing the precise cause (mainly for advising other family members about risks of developing the condition) the lack of such knowledge does not affect the basic management of the condition.

How is CMT treated?

At present there is no specific drug or genetic treatment. But much can be done to help and support the individual – important members of the care team include physiotherapists, occupational therapists and orthotists (who make splints and other aids).

Inheritance patterns and prenatal diagnosis

Inheritance patterns
Three patterns of inheritance are noted. Autosomal dominant is the most common pattern of inheritance. Autosomal recessive inheritance is the least common. X-linked inheritance has been noted where the condition may be passed to both sons and daughters – affected sons will usually display more severe symptoms.

Prenatal diagnosis
In families who have type 1a prenatal diagnosis is now becoming available but is rarely requested.

Support for people with CMT and their families

f your child is affected by a medical condition or disability, we can help. Call our freephone helpline on 0808 808 3555 to get information, support and advice. We also offer emotional support for parents via our Listening Ear service.

We have a range of parent guides on aspects of caring for a disabled child in our resource library. You may also find our Early Years Support useful, which contains links to parent carer workshops and help for families going through the diagnosis process.

We’ve listed a support group below and you can also meet other parents online in our closed Facebook group.

CMTUK

Freephone helpline: 0300 323 6316 or 01202 474203 available between 9am – 2pm Monday to Friday(except Bank Holidays)
Email: [email protected]
Website: cmt.org.uk

CMTUK are a registered Charity in England and Wales No. 1112370. CMTUK is working to support people living with Charcot-Marie-Tooth Disease (also known also known as Hereditary Motor and Sensory Neuropathy) and their families and carers.

They have publications available on a variety of CMT related topics including suitable information for Schools as well as an open and Members Facebook group. They offer Regional Support Groups throughout the UK, for members, that regularly meet online using ZOOM or arrange a local meetup. It is a great way to keep in touch with others with CMT.

They have a CMT Kids Support Group with their own Facebook page, they hold activity camps for the 11-18 year olds and day trips for the younger ones such as LEGOLAND, Chester Zoo and The Deep Aquarium. CMT Kids also on a weekly basis hold a Quiz Night or Games Night on ZOOM, fun is had by all.

Group details last updated July 2022.

Products and aids for people with CMT

Visit Fledglings, our non-profit shop where we supply products to help children and adults with Charcot-Marie-Tooth disease.

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Credits

Medical text written November 1991 by Contact a Family. Approved November 1991 by Professor M Patton, Professor of Medical Genetics, St Georges Hospital Medical School, London, UK and Dr J E Wraith, Consultant Paediatrician, Royal Manchester Children’s Hospital, Manchester, UK. Last updated September 2010 by Dr David Hilton-Jones, Clinical Director, Muscle and Nerve Centre, Radcliffe Infirmary, Oxford, UK.