NEUROFIBROMATOSIS

The hallmark of neurofibromatosis type I in the neonatal period is the presence of cafe au lait spots (Figure 301.1). The presence of six or more cafe au lait spots larger than 1 cm in diameter establishes the diagnosis in young children. Neonates with less than six spots, even if smaller than 1 cm, may have neurofibromatosis because the number and size of the cafe au lait spots increases after birth.

Figure 301.1.— Two cafe au lait spots in a neonate with neurofibromatosis.

Neurofibromatosis does not usually produce neurological manifestations in the neonatal period. Nevertheless, the possibility of dysplastic tumor of the central or peripheral nervous system should be considered in any patient with neurofibromatosis who develops a neurological deficit. Careful ophthalmological evaluation should be performed and, if inconclusive or if an optical disc abnormality is found, an MRI of the brain should be done to exclude the possibility of optic glioma. Lisch nodules of the iris and axillary freckling are usually not present in the neonate. Neurofibromatosis is an autosomal dominant disorder with 100% penetrance but variable expression. Spontaneous mutations are frequent. The gene locus is 17q11.2.