RT Journal Article SR Electronic T1 Correspondence JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 324 OP 324 DO 10.1136/jmg.17.4.324-a VO 17 IS 4 A1 Elizabeth Riley A1 Michael Swift YR 1980 UL http://jmg.bmj.com/content/17/4/324.2.abstract AB