The discovery of dozens of new abnormal chromosomes may provide more information to scientists for genetic and cloning researches, claim experts at a research institute in Guangzhou, South China's Guangdong Province.

Scientists at the Technological Centre for Healthy Birth under the Guangdong Family Planning Research Institute have discovered 39 cases of abnormal chromosomal karyotypes, which are not thought to have been recorded anywhere else in the world.

Director of the centre Zheng Lixin told China Daily yesterday the cases have been verified by the National Laboratory of Medical Genetics in Central China's Hunan Province.

The new discoveries follow the analysis of 5,000 blood samples since 1996, bringing the number of abnormal chromosomal karyotypes cases first reported by Chinese scientists to 1,838, Zheng said.

In one of the cases, a 4-year-old girl lost her genetic ability for inhibiting retinoblastoma, a tumour in the retina, from developing into cancer.

In another case, it was discovered a 22-year-old female patient was born without a womb. Tests showed an abnormal chromosomal karyotype led to a loss of a gene decisive for the formation of the womb.

The scientists also discovered that an abnormal chromosomal karyotype caused the low sperm count of a pair of twin brothers.

Some inherited diseases and low reproductive capacities resulting from abnormal chromosomal karyotypes cannot be cured effectively at present, Zheng said.

Doctors, being made aware of the abnormalities in their patients, can then provide clinical advice. They may, for example, suggest that couples have artificial insemination or adopt children, to prevent defective births.

Zheng said the new discoveries would help to boost the efforts of scientists in the fields of genetics and cloning.

Abnormal chromosomal karyotypes may be attributable to chemicals, radioactive materials or biological viruses. Discoveries of them also serve as indirect indices in assessing environmental pollution, he said.

Editor: Yan