Scientists use gene therapy to treat infertility

Male sterility caused by missing sperm has been treated successfully through gene therapy in which DNA is injected into tissues to replace defective genes.

Male sterility caused by missing sperm has been treated successfully through gene therapy in which DNA is injected into tissues to replace defective genes.

A study using male mice carrying a genetic defect that blocks sperm production has shown for the first time that gene therapy on testicular tissue can restore fertility.

Scientists in Japan, led by Takashi Shinohara of Kyoto University, have demonstrated that inserting healthy copies of the gene into the sterile males can unblock sperm production. They did the gene therapy on the Sertoli cells of the testes, which provide nutrients and nourishment to the "germ" cells that produce sperm.

Some of the infertile mice used in the experiment began to produce immature sperm cells and in one case the sperm was mature enough to inject into unfertilised eggs to produce healthy offspring.

The scientists said, in a scientific paper published yesterday in the Proceedings of the National Academy of Sciences, that gene therapy could be used to treat infertile men with similar inherited defects. "Our successful production of offspring from an infertile male mouse suggests a promising possibility for the gene therapy approach in the treatment of male infertility," the scientists said.

About one in five couples experience difficulty in having a baby and about 20 per cent of these cases are caused solely by male infertility.

Professor Norman Nevin, chairman of the Government's Gene Therapy Advisory Committee, said the study would have to be replicated before human clinical trials in Britain would be permitted.

* The Christie Hospital in Manchester says that the transplant of testicular tissue may have helped a man who had cancer treatment to father a child. The man had the tissue stored in ice before he received chemotherapy, which usually results in sterility.