The inheritance pattern of dysplastic naevi in families of dysplastic naevus patients

Dysplastic naevi (DN) are the major precursor lesions of malignant melanoma, yet the presumed mode of inheritance or genetic aetiology of DN remains controversial. The inheritance pattern of DN in families from a randomly selected population of 26 dysplastic naevus patients was investigated by estimating the segregation ratio in families ascertained through an offspring with DN (incomplete ascertainment). For families ascertained through a parent with DN (complete ascertainment) the transmission pattern was examined by comparing the observed number of affected offspring to the expected number using a chi 2 goodness-of-fit test. Results from the chi 2 tests and the estimated segregation ratio of 0.52 (95% confidence interval: 0.31, 0.73) suggest that the inheritance pattern for dysplastic naevi in these families is consistent with autosomal dominant transmission, although the present study was limited because of a small sample size. The findings, therefore, need to be confirmed by a much larger study that is able to test more rigorously specific genetic hypotheses.