The new DD gene, called MYH7, carries instructions for a protein known as a myosin heavy chain. It ™s needed in heart and skeletal muscle cells, and abnormalities in it have previously been found to cause cardiomyopathy (cardiac muscle disease) and myosin storage myopathy, a muscle disease.

The new link between MYH7 and DD was published online in the American Journal of Human Genetics on Aug. 20.

DD, which weakens the muscles of the forearms, hands, lower legs and feet, can result from flaws in at least seven (four known and at least three unidentified) genes for proteins affecting muscles.

The MYH7 form, which can cause symptoms as early as age 4, is known as Laing early-onset distal MD (or distal myopathy). Nigel Laing and colleagues narrowed the location of the disease-causing gene flaw to chromosome 14 in 1995. People with Laing DD usually don ™t have cardiomyopathy.

The precise identification of disease-causing gene flaws (mutations) generally leads to improved diagnostic procedures right away, and to improved treatment in the long run.

mdausa/

Third, public health agencies need to engage in discussions with pharmaceutical companies to explore areas of common interest in vaccine development and identify areas where support is needed. Since 2003, when two cases of human H5N1 infection occurred in Hong Kong SAR, WHO has worked to identify and resolve problems in order to pave the way for rapid development and production of a pandemic vaccine.

Vaccine manufacturers respond to market forces. Companies may be reluctant to produce a vaccine for an event, such as a pandemic, that cannot be predicted with any certainty and might not be caused by currently circulating strains. Some uncertainty has also centered on rights to use the special technique of reverse genetics, a patented procedure, that is needed to produce the prototype seed vaccine against H5N1.

At the beginning of April 2004, WHO made the prototype seed strain for an H5N1 vaccine available to manufacturers. To date, only two of the world ™s roughly 12 major companies producing influenza vaccines have taken work on a pandemic vaccine significantly forward. These two companies, Aventis Pasteur Inc. and Chiron Corp., both located in the USA, have produced small batches of vaccine for use in clinical trials. These trials, which require several months for the compilation and analysis of data, are needed to fine-tune vaccine composition, test safety, and meet other licensing requirements. Trials are not expected to begin before year-end.

who.int