DRUGS already used for other conditions may in the future be used to help women to combat urinary incontinence.
Speaking at the annual conference of the European Society of Human Genetics in May, Dr Rufus Cartwright said while genetic or heritable factors were known to contribute to half of all cases, until now studies had failed to identify the genetic variants associated with the condition.
Almost half of adult women experience leakage at least occasionally. Pelvic floor disorders, including urinary incontinence, as well as faecal incontinence and pelvic organ prolapse, have a devastating effect on quality of life.
Of the 25 per cent of women who are affected sufficiently for it to impact their daily lives, most suffer from stress incontinence - the loss of small amounts of urine associated with laughing, coughing, sneezing, exercising or other movements that increase pressure on the bladder.
Isolated urgency incontinence - where a sudden pressing need to urinate causes the leakage of urine - affects only about 5 per cent of women; 5-10 per cent have a combination of both forms.
Dr Cartwright's researchers, from the Department of Epidemiology and Biostatics at Imperial College, London, undertook a genome-wide association study in just under 9000 women from three groups in Finland and the UK, confirming their findings in a further six studies.
Analysis of the study data yielded a risk locus for urinary incontinence close to the endothelin gene, known to be involved in the ability of the bladder to contract.
Drugs that work on the endothelin pathway are already used in the treatment of pulmonary hypertension and Raynaud's syndrome, a condition where spasm of the arteries causes reduced blood flow, most usually to the fingers.
"Previous studies had failed to confirm any genetic causes for incontinence," Dr Cartwright said.
"Although I was always hopeful we would find something significant, there were major challenges involved in finding enough women to participate, and then collecting the information about incontinence.
"It has taken more than five years of work and has only been possible thanks to the existence of high quality cohort studies with participants who were keen to help."
Current treatment for urinary incontinence in women includes pelvic floor and bladder training, advice on lifestyle changes (for example, reducing fluid intake and losing weight), drugs to reduce bladder contraction, and surgery.
However, as the number of identified risk variants for urinary incontinence grows, there will be potential to introduce genetic screening for the condition.
Conference chair, Professor Joris Veltman of the Institute of Genetic Medicine at Newcastle University, UK, said the work "reveals the first links between urinary incontinence and genetic factors. It provides important insight into the biological mechanisms for incontinence."
