On the cover: Alexis “Lexye” Mortimer, center, has spinal muscular atrophy (SMA). Pictured here with her parents, Joe and Melissa, and her twin siblings, Jory and Aaron, Lexye was the 2005 MDA Oklahoma Goodwill Ambassador. Dear Friends What is a Genetic Disorder? What is Genetic Testing? How are Genetic Disorders Inherited? What Happens in Actual Families? What May Happen in a Family With Duchenne MD What May Happen in a Family With Spinal Muscular Atrophy What May Happen in a Family With Myotonic MD Are There Genes Outside the Cell's Nucleus? MDA is Here to Help You

Dear Friends:

Most of the neuromuscular disorders in the Muscular Dystrophy Association’s program are genetic, and MDA’s worldwide research program has discovered the genetic causes and inheritance patterns of dozens of these diseases. Building on these recent findings, MDA-supported investigators are exploring a world of potential treatments.

“Facts about Genetics and Neuromuscular Diseases” gives an up-to-date review of genetics information relating to neuromuscular diseases.

This booklet describes what a genetic disorder is and explains how genetic testing and counseling can help people understand how disorders that may affect themselves or their children are inherited. It also gives examples of the major patterns of inheritance, with specific neuromuscular diseases as examples. Finally, it looks at mitochondrial inheritance, an aspect of genetics whose importance is becoming increasingly appreciated.

If you have a neuromuscular disease, or would like to know more about a particular disease in MDA’s program, ask at your local MDA office for the booklet covering that disorder.

You also can find out more about MDA’s services and other programs, keep current on new research, and get information on medical and disability issues by reading other MDA publications, visiting www.mda.org on the Internet or calling (800) 572-1717.