Genetics company Oxagen is to collaborate with a US biotech firm to identify a gene for osteoporosis, the brittle bone disease that affects 75 million women in the USA, Europe and Japan.

It is the fourth cause of disease-related death of women, who can lose bone density rapidly after the menopause unless they take hormone replacement therapy.

Oxagen, based at Milton Park, near Abingdon, will join Incyte Genomics, of Palo Alto, California, to look at the link between certain genes and bone mineral density, fractures and other symptoms. The companies will share their databases. Incyte has identified possible genes and Oxagen has set up the family osteoporosis study group, involving leading researchers in Oxford, Cambridge, and other European cities. The genes will be tested against 3,600 samples from Oxagen's collection.

Chief executive Trevor Nicholls said: "This collaboration could lead to genuine breakthroughs."

Oxagen is speeding up its search for the genes responsible for other common human diseases with an agreement to use technology known as SNiPer, single nucleotide polymorphism (SNP) genotyping, from Amersham Pharmacia Biotech. Oxagen, which employs 90 people, has raised £30m from business angels for its work analysing blood and other samples from families with ailments such as heart disease, asthma or osteoporosis. Later this year, it expects to be analysing more than five million genotypes.

Mr Nicholls said: "SNP genotyping is one of the core functions within Oxagen's operations.

"It is essential that we have access to a system that can be used flexibly on a low-cost basis.

"SNiPer promises to deliver low costs per genotype and we are delighted to have access to this technology."