An epidemiological study of Wolf-Hirschhorn syndrome: life expectancy and cause of mortality

Objective-Early research into Wolf-Hirschhorn syndrome (WHS) described a hi gh mortality and no relationship between deletion size and phenotype. This may need to be revised in the light of improved cytogenetic resolution and medical care. We have collected epidemiological data to allow the calculati on of birth incidence and mortality figures. In addition, we have investiga ted the possibility of a relationship between deletion size and mortality. Method-Information relating to past and present cases diagnosed in the UK w as collected by multiple ascertainment. Results-A total of 159 cases were collected. The status (alive or dead) was determined for 146, of whom 96 are alive, 37 had died, and 13 were detecte d on prenatal diagnostic tests. A minimum birth incidence of 1 in 95 896 wa s calculated. The crude infant mortality rate was 17% (23/132) and in the f irst two years of life the mortality rate was 21% (28/132). Cases with larg e de novo deletions (proximal to and including p15.2) were more likely to h ave died than those with smaller deletions (odds ratio=5.7, 95% CI=1.7-19.9 ) after adjusting for age. A comparison of survival curves for de novo dele tions and translocations did not show a statistically significant differenc e (p=0.11). The median survival time for de novo deletions was 34+ years wh ile for translocation cases it was 18+ years. Conclusions-The mortality rate is lower than previously reported. There is a statistically significant relationship between deletion size and overall risk of death in de novo deletion cases. The difference in survival curves between de novo deletions and translocations is not statistically significa nt.