Guy's and St Thomas' Hospital

The four genes so far identified as causing myotubular and centronuclear myopathy, namely MTM1, DNM2, RYR1 and BIN1, can all now be tested for in the UK by Dr Stephen Abbs and his team at a diagnostic DNA laboratory in Guy's & St Thomas' Hospital, London.

The request for testing genes for mistakes must be made by either a neurologist with expertise in the diagnosis of myopathies or a genetics doctor. In addition to a detailed clinical assessment, muscle MR imaging and a muscle biopsy may be performed as a prerequisite for informed genetic testing.

As part of the genetic testing, a clinical geneticist will ask questions about the family, in order to ascertain the pattern of inheritance of the myopathy within the family and where appropriate, gene testing may then be requested.

Paediatric Neurology colleagues running the tertiary Neuromuscular Service at the Evelina Children's Hospital, have a special clinical and research interest in centronuclear and related congenital myopathies and would be interested to review a child with any of these conditions prior to genetic testing.

MTM1

Mistakes in the MTM1 gene cause the commonest form of myotubular myopathy, which is inherited in an x-linked way. The methods used to test the MTM1 gene for mistakes detect most mistakes in the MTM1 gene. Testing for mistakes in the MTM1 gene takes approximately 8 weeks.

For patients eligible for NHS care, gene testing in the MTM1 gene is available on the NHS, so does not therefore need to be paid for by the patient.

For those who are not eligible for NHS care, there is a charge of £290 for testing the MTM1 gene.

BIN1, DNM2 and RYR1

Centronuclear / myotubular myopathy inherited in either an autosomal dominant or an autosomal recessive way is caused by gene mistakes in the BIN1, DNM2 and RYR1 genes. Less information is available about these genes, and it is not possible to say accurately what percentage of gene mistakes the laboratory is able to detect, but it will be able to detect the majority of gene mistakes.

For those who are eligible for NHS care, gene testing for BIN1, DNM2 and RYR1 is available on the NHS, so does not therefore need to be paid for by the patient but for those who are not eligible for NHS care, the following charges apply.

• BIN1: £290
• DNM2: £330
• RYR1: £1,435

For requests for genetic testing in MTM / CNM patients from abroad, a referral letter should be sent to Dr Heinz Jungbluth at the address below, outlining the patient's salient clinical and muscle biopsy findings in order to allow an informed choice of the appropriate genetic test. A copy of the muscle biopsy report, digital images from the muscle biopsy or the original muscle biopsy slides are also very helpful in determining the appropriate test.

Heinz Jungbluth
Senior Lecturer and Consultant in Paediatric Neurology
Department of Paediatric Neurology - Neuromuscular Service
Evelina Children's Hospital - 6th Floor, Sky
St. Thomas' Hospital
Lambeth Palace Road
London SE1 7EH
United Kingdom

Telephone: 0207 188 3998 (secretary)
Fax: 0207 188 0851

For further information or to check for the most current charges, please contact Guy's and St Thomas' Hospital.