THE GARY WOODWARD DYSKERATOSIS CONGENITA TRUST
Registered Charity no: 1113617
HOW IS DYSKERATOSIS CONGENITA INHERITED?
There are 3 ways that DC can be inherited this is called X linked- Recessive, Autosomal Dominant and Autosomal Recessive. Learning about inheritance patterns can be complex and this is why it is a good idea to discuss this with your Consultant who may be able to explain some of the terminology more simply.
X LINKED RECESSIVE
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DC can be inherited and one of the most common patterns of inheritance is called X linked-recessive. In these families the gene responsible for DC is carried on the X chromosome and this was the first DC gene to be identified in 1998. Female carriers of the X linked gene can be diagnosed antenatally by DNA analysis for this gene (DKC1).
If you would like more in-depth information about the mutations in the genes please see below:
This is a schematic representation of the DKC1 gene showing some of the mutations (genetic defects) that are seen in patients with X-linked DC.
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This diagram is kindly reproduced with permission from Professor Inderjeet Dokal.
AUTOSOMAL DOMINANT:
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There are 3 subtypes in this category. The genes affected in this category are TERC, TERT and TINF2. Genetic testing is available for these genes.
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AUTOSOMAL RECESSIVE:
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This sub-type is very diverse and genetic diagnosis is not always possible.
The diagram below shows some of the complexes involved in telomere maintenance. Telomeres are the area at the end of a chromosome (which is important for cell growth and repair) these are important for cell life and if they become shortened as in DC this can affect the life of the cells and also the genes responsible for growth and repair. This results in changes to the body’s cells and can be linked to some disease processes such as DC (Dokal & Kirwan, 2009).
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This diagram is kindly reproduced with permission from Professor Inderjeet Dokal.
TESTING
How are people tested for DC?
Blood samples from the patient are used to extract DNA. This DNA can then be tested for the different genes associated with DC.
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How long does testing take and how do people the get results?
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This is usually a few weeks to months.
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Who can I discuss the results with?
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Your specialist doctor. You can also contact Professor Inderjeet Dokal for further information.
DYSKERATOSIS CONGENITA REGISTER
What is the Dyskeratosis Congenita Registry?
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To improve the method of diagnosis and provide the possibility of new treatments, doctors at The Royal London Hospital (Barts and The London School of Medicine) have established a DC registry. This has allowed identification of several of the genes responsible for DC and now permits genetic testing in many families.
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The DC registry is an international registry of patients and families which was founded and has been co-ordinated since 1995 by Professor Inderjeet Dokal; the aims are to co-ordinate a clinical service and expedite research. Currently on the registry there are 430 families. The number of families in the UK affected by DC are 48.
For further information about the DC registry please contact:
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Professor Inderjeet Dokal
Centre for Genomics and Child Health
Blizard Institute
Barts and The London School of Medicine and Dentistry
Queen Mary University of London
Blizard Building
4 Newark Street
London
E1 2AT
Tel: 020 7882 2205
RESEARCH
What is being done to help with research?
Dyskeratosis Congenita is a severe bone marrow failure syndrome which is a genetic disorder that can affect many systems of the body.
It is important that more research is carried out to find answers about the function of these genes and the common patterns of inheritance. It is also important to understand the genetic basis of the uncharacterized DC cases.
The Gary Woodward Dyskeratosis Congenita Trust is supporting research into the biology of DC to try to discover how the genes work and how they are inherited. At present we understand that the end of chromosomes (telomeres) are affected and this causes the cells of the body and body organs to age quickly and earlier for some people which causes symptoms of Dyskeratosis Congenita. (Dyskeratosis Congenita Dokal Hematology Am Soc Hematol Educ Programm 2011: 480-6)
The long term aim of the research is to improve the quality of life for those affected by the condition.