Neurofibromatosis, Type Iv, Of Riccardi

Riccardi (1982) described cases of neurofibromatosis that are sufficiently variant that they seem to warrant separation from the classic von Recklinghausen NF I (162200), the acoustic neuroma type, NF II (101000), and the mixed type, NF III (162260). The group still is undoubtedly heterogeneous. Iris Lisch nodules, one of the most specific features of NF I, are usually absent in NF IV. The importance of a separate category for these cases is related to the probable difference in prognosis and genetic counseling and the desirability of avoiding confusion of studies of the natural history and pathogenesis of NF I.