Tracing What Triggers Diabetes

Researchers reported yesterday that they had confirmed that type 1 diabetes is triggered by the body's immune system turning on delicate cells.

The findings could lead to a vaccine against the disease that affects more than 1 million Americans, said Susan Wong and colleagues at Yale University School of Medicine.

Writing in the journal Nature Medicine, Wong's team said they found an antigen--a protein that stimulates an immune response--in mice specially bred to develop what looks like human juvenile diabetes.

Type 1 diabetes, known as juvenile diabetes, occurs when the immune system attacks the pancreatic beta cells that produce insulin for the body. People with type 1 diabetes do not produce enough insulin and must carefully monitor their blood sugar levels and take insulin to control them.

There is no cure and failure to control blood sugar levels can cause blindness, limb loss and early death.

Type 2, or adult-onset, diabetes is far more common and seems related to diet and lack of exercise.

Genetics and Wake-Sleep Cycle

A sleep syndrome that sends people early to bed and early to rise doesn't necessarily make them healthy, wealthy and wise.

The disorder, traced to a single gene, can send sufferers to bed when everybody else is still going strong, researchers at the University of Utah have found.

Understanding what governs people's wake-sleep cycles has important medical implications for dealing with insomnia, jet lag, shift work and depression, the scientists report in Nature Medicine.

Researchers studied people with a shorter than normal wake-sleep cycle. Regardless of work schedules or social pressures, these people can't stay up much later than 8:30 p.m. and tend to wake up around 5:30 a.m.

It's called "familial advanced sleep-phase syndrome" because it shifts the normal wake-sleep pattern forward by three to four hours.

Louis Ptacek and colleagues found 29 people in three families with the disorder. One family included a grandmother, daughter and grandchild with the same sleep disturbance.

Most creatures seem to operate on a biological clock approximately synchronized to a 24-hour day. This rhythm controls a variety of daily biochemical and behavioral cycles including fluctuations in sleep and wakefulness. For people with this syndrome the cycle is shorter and the constant conflict between their body clock and coping with the rest of the world leads to their shifted sleep-wake rhythm.

By studying the family relationships the scientists found that the disorder is inherited in a way common to other inherited traits caused by a single gene, such as eye color.

Ptacek's team is working to identify the gene responsible. Finding it could lead to the protein it produces to cause the body's time shift--which could then lead to the development of drugs to treat not only the sleep disorder, but jet lag and other conditions.