Malformations of the auricle: isolated and in syndromes IV. Cumulative pedigree data

In dominant inheritance with incomplete penetrance, recurrence risks should be the same, regardless of the parental phenotype. In multifactorial inheritance, on the other hand, an affected parent will increase the risk to subsequent offspring. In our analysis, recurrence rates were higher in families with an affected parent (P < 0.01), lending support to the multifactorial concept. These data suggest the following conclusions: Auricular and mandibular malformations, particularly in the presence of associated anomalies, occur in relatives of probands in frequencies and patterns highly suggestive of multifactorial inheritance. Because other modes of inheritance may also explain observed patterns, complex segregation analysis is planned, following accumulation of additional fully documented pedigrees.