Useful information about rare inherited disorders

Rare disorders from Aarskog syndrome to the Zellweger syndrome do not appear in standard textbooks. Although individually rare, such inherited disorders number in thousands when considered together and form a significant proportion of disease. A patient with one of these disorders is likely to be seen in general practice from time to time. Fortunately for practitioners, several sources for reference now exist that could help in the management of patients and their families.

The charitable sector often provides a good source of information for both patients and professionals. The charity Contact a Family (www.cafamily.org.uk/) has pioneered this with its first directory, published in 1991.¹ Hard copies on paper or on CD are available from the charity. This directory is now updated regularly and available free on the internet. It provides summaries of the disease that are written by experts and contact details of patient support groups. The website is widely used by healthcare professionals, but glossaries are also available, to explain genetic terms or medical terminology, with links to reputable medical sites on the internet. A similar directory and website provided by the National Organisation for Rare Disorders (www.rarediseases.org) provides information and links with patients' support groups in North America.²

Doctors recommending a support group will find that it is very helpful for many families, who will come in contact with other families and share their problems. However, the encounter can be stressful for patients whose condition was diagnosed recently and for their families as it may bring them face to face with patients who have severe manifestations of the disease. Doctors should first review the information given by the patients' group and discuss this problem with families before recommending the resource.

Patients without a diagnosis cannot be helped by this resource as support groups aim to help those with specific diseases. So what about children in whom there clearly is some form of a rare syndrome, yet no diagnosis has been made? They are not left without support as there is a group—Syndromes without a Name—for undiagnosed syndromes listed on the directory.

If the rare disease is caused by a single gene disorder an excellent resource for information is provided by the National Institutes for Health in the United States. Online Mendelian Inheritance in Man (www.ncbi.nlm.nih.gov/omim/) provides detailed clinical reviews for 14 184 single gene disorders, together with the latest genetic research. The information provided on this site is being updated continually and is reviewed by experts. The site also provides a comprehensive list of references, which can then be accessed through a link to PubMed. More adventurous and curious users may explore the links to genetic databases in the fruit fly, mouse, and other animal species. This internet resource is a practical example of how the human genome mapping project is disseminating genetic information and can benefit physicians from various specialties.

What is rare for the generalist may be common for the specialist. Regional genetic services cover populations of around three million and therefore develop clinical expertise in many rare inherited disorders. Direct contact with or referral to the clinical genetic staff will answer specific questions and provide more support and access to diagnostic testing. A list of the regional genetic centres is provided on Contact a Family's website.

Where textbooks have not provided an answer about a rare inherited disorder many answers are now available with relative ease of access beyond textbooks.