[Phylloid hypomelanosis and mosaic trisomy 13: a new etiologically defined neurocutaneous syndrome].

The term phylloid hypomelanosis is proposed to denote a new etiologically defined neurocutaneous syndrome. The hallmark of this trait is a pattern of hypopigmentation consisting of round or oval lesions, large asymmetrical areas reminiscent of the leaves of a begonia, as well as pear-shaped areas or oblong macules. The term phylloid pattern is derived from Greek phyllon=leaf and eidos=form. In 5 out of 6 cases in which cytogenetic findings were reported, a mosaic trisomy 13 or translocation trisomy 13 was found. All patients showed CNS defects with mental retardation. In addition, absence of corpus callosum, conductive hearing loss, choroidal and retinal coloboma,cranio-facial defects as well as brachydactyly,clinodactyly, camptodactyly and other skeletal anomalies were reported. In contrast to hypomelanosis of Ito which is associated with many different forms of genetic mosaicism, phylloid hypomelanosis most likely represents a cytogenetically rather uniform neurocutaneous phenotype.