*Note: In the print edition of Quest, this article was titled "Rounding Up the Usual -- and Not So Usual -- Suspects."

The scene is familiar to everyone who watches crime dramas. The safe has been opened, and the hotel guests' jewelry and other valuables are missing. What happened, and when, and who's responsible?

The trouble started for Claire Walker when she was in kindergarten, when her physical education teacher noticed that she couldn't do sit-ups like the other children and that her back seemed "lopsided." Claire's parents took her from their home in Louisiana to see Yadollah Harati, an MDA-affiliated neuromuscular disease specialist at Baylor College of Medicine in Houston.

There, she learned she had facioscapulohumeral (FSH) muscular dystrophy, a muscle-wasting disease that mostly affects the muscles of the face and upper body but can also affect the back and legs.

Some people have nightmares about falling off cliffs. Brad Williams has nightmares about falling — period.

“Whenever I’m walking, falling down is always the major thought on my mind,” says Williams, 39, of Alexandria, Va. “It has to be on my mind a lot for me to be dreaming about it.”

Williams has Miyoshi distal myopathy, a slowly progressive form of muscular dystrophy that primarily affects the extremities. He hosts an MDA Internet chat under the nickname “dysf,” and notes that other chat participants also have reported falling nightmares.

Wendy Salo's doctors told her she was suffering from stress — or perhaps chronic fatigue syndrome. But Salo knew there was something else going on.

At the time, she was in her late 30s. Admittedly, she had reason to be tired and stressed. She had a full-time job developing software for banks, and she had a husband and two teen-age sons.

But, to her way of thinking, those factors couldn't account for her nearly falling asleep at the wheel during the 15-minute drive between work and home, or being unable to climb the stairs to her office after her lunch break.

Sheila Smith of Brookhaven, Miss., can't get over the feeling that myotonic dystrophy is an unwelcome, and unexpected, intruder in her family.

It started in November 1998, when her husband, Michael, then 33, had a car accident. "We feel that he fell asleep at the wheel," Sheila says.

The year was 1992, and neurologist John Day had recently moved from the University of California at San Francisco to the University of Minnesota at Minneapolis, where he was to assume the directorship of the MDA clinic. (Day still holds this position, at what is now the Fairview-University Medical Center. He's also an associate professor of neurology at the university.)

Earlier that year, a genetic defect underlying myotonic muscular dystrophy (MMD) had been identified by MDA-supported researchers, and a genetic test for it had just been made available.

Tom Baker, 14, is the second child of Harold and JoAnn Baker of Dover, Ohio. When he was a small boy, the family noticed that he walked "funny," certainly not like their first child, Jessica, now 18, or their youngest, Lisa, 11.

Still, doctors weren't terribly concerned until the Bakers took Tom for his kindergarten physical. "The doctor noticed that he exhibited the Gowers' sign," JoAnn recalls, referring to the way children with leg muscle weakness use their arms to brace themselves when getting up from the floor.

Part 1 of this series(Quest, Vol. 6, No. 2) addressed cardiomyopathy, the degeneration of heart muscle that often occurs in many neuromuscular diseases.

Cardiac problems are common in several neuromuscular disorders. They can be quite serious, particularly in Duchenne and Becker muscular dystrophy (DMD and BMD). In this, the first of a two-part series, we'll explore cardiomyopathy, the type of heart problem that's found most often in DMD and BMD and also occurs in some other neuromuscular conditions. (Read Part 2 of this series.)

The reasoning is sound: A female has two X chromosomes to a male's one, so she has a built-in "backup" if anything should go wrong on either of her two Xs. She can be a "carrier" of an X-linked disease, because she can give a flawed X chromosome to her sons, who, having only one X, will likely develop an X-linked disorder.

DMD is one of many X-linked diseases, such as two kinds of hemophilia (including one that affected generations of European royalty) and red-green color blindness.