Discounting an adverse maternal effect on severity of neurofibromatosis.

Neurofibromatosis, a common, progressive, autosomal dominant disorder, is markedly variable in its expressivity. Some authors have suggested that some contribution to neurofibromatosis's variability may be an adverse effect of a mother's neurofibromatosis on the overall severity seen in her offspring with neurofibromatosis. In the present study of 188 maternal affected, paternal affected, and sporadic von Recklinghausen neurofibromatosis cases, the maternal influence question was systematically examined. Overall severity, selected features most likely to reflect in utero maternal influence, and other common neurofibromatosis-I features were analyzed statistically. Age, racial composition, and gender of the three groups were similar. No significant differences were found (P less than or equal to .01) between maternal affected, paternal affected, and sporadic cases in terms of overall severity, probability of reaching advanced severity as a function of age, indications of possible prenatal influence (eg, congenital neurofibromas, tibial pseudarthrosis), or other neurofibromatosis features. These results demonstrate that the nature and severity of neurofibromatosis for maternal affected cases are essentially the same as for paternal affected and sporadic cases.