Genetics of diabetes

SHENZHEN, China, Feb 24 (Reuters) - Chinese scientists are trying to find out which errant genes are responsible for diabetes and certain forms of cancer that have long plagued Chinese populations, a geneticist said.

Rising affluence, richer diets and a sedentary lifestyle have led to an alarming rise in cases of diabetes in China in recent decades, while cancers of the oesophagus, lungs, breast, stomach and colon have plagued Chinese people for a much longer time.

The partly state-funded Beijing Genomics Institute (BGI), which completed the mapping out of the first Chinese human genome in 2007, is trying to figure out which genes may be responsible for these chronic and even terminal illnesses.

"We are doing disease gene mapping, to find causal (gene) variants for certain diseases in Chinese populations," said Gao Yang, vice general manager of BGI's Shenzhen branch, which was mainly responsible for the sequencing of the first Chinese genome.

"We are most interested in diabetes and five types of cancer."

BGI is collaborating with Chinese hospitals on the cancer project and foreign institutions on diabetes.

"We will be sequencing DNA samples provided by hospitals," Gao told Reuters in a weekend interview.

Chinese doctors now rely on western data when making diagnoses and deciding on drug protocols, which Gao said was far from ideal.

"When deciding how to administer drugs to a Chinese breast cancer patient, for example, it's important to consider her genetic makeup. From diagnosis to drug dosage, it may be a very different story," said Gao.

"With our own data, we can have personalised medicine. Even if it's the same disease, you may need a different drug or dosage if you have a different genetic makeup."

SEQUENCING THE PANDA GENOME

The institute is currently mapping out the genome of China's giant panda. "We may use the information to better protect this endangered species and understand its evolution," said Gao.

The institute also has its eye on a few infectious agents, such as the Hepatitis B and human papilloma viruses (HPV) that are especially problematic for Chinese populations -- although a better or faster cure may be decades away.

Asia is largely ignorant about Hepatitis B, the 10th leading cause of death worldwide. Chronic Hepatitis B affects 360 million people globally, and of these, 281 million are in Asia.

One in four will die from either cirrhosis, or scarring of the liver, or liver cancer later in life.

HPV is a major cause of cervical cancer.

"We want to develop better (and less expensive) detection tools. For now, HPV detection kits are very expensive and HPV infections mainly take place in poorer areas," Gao said.

"As for Hepatitis B virus, drug resistance is serious, so we need to design more sensitive and cost effective diagnostic tools. By sequencing the virus, we can see how it is mutating, so that better drugs can be designed," he said.
Experts say 10 percent of China's more than 1.3 billion population carry the Hepatitis B virus, with the figure reaching as high as 16 percent in certain parts in the south.

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