RT Journal Article SR Electronic T1 International Journal of Epidemiology JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 100 OP 100 DO 10.1136/jmg.10.1.100-a VO 10 IS 1 YR 1973 UL http://jmg.bmj.com/content/10/1/100.2.abstract AB