Backache is the second major cause of employee absenteeism after common cold. Now, Susanna Annunen and her team from the University of Oulu in Finland report that inter-vertebral disk disease, also called sciatica, may well run in the families with a gene called COL9A2 that is responsible for the condition. Sciatica is a painful condition in the region of the lower back and hip, affecting about half of all people with serious back conditions. In many cases, it causes numbness, abnormal sensitivity and tingling. The scientists confirmed the theory by studying 26 unrelated people suffering from such back ache; all were found to carry such a gene. Further, when the family backgrounds of two such subjects were examined, it was found that all members of the two families who had inherited this gene had sciatica diagnoses. In the control group of 174 people, who did not have the disease, the gene was not found. Bone specialists say that this study explains why some people with unusually rigorous lifestyles never experience back problems while others with normal lifestyles unexpectedly develop serious back conditions ( Science , Vol 285, No 5426).