Laurin-Sandrow syndrome: review and redefinition

We report on a newborn infant with characteristics of Laurin-Sandrow syndrome (LSS). She had hypertelorism, flat nose with grooved collumella, "V" shaped mouth with thin lips, 7 well-recognized and fused digits and 1 additional postaxial bilateral appendix on each hand. The right and left feet had 12 and 11 toes, respectively, the 4 external ones were recognizable, and the rest were fused in a uniform mass but with independent nails. There was also a 2.3 cm-long digitiform appendix in the internal part of both feet. Radiographs showed seven metacarpals and seven metatarsals with similar morphology; both hands lacking thumbs. The four lateral-most toes had regular shaped phalanges and the rest were irregular. The left digitiform appendix had three bones and the right only two. Tibiae were shorter than fibulae. Central Nervous System examination showed an abnormally shaped olivary nucleus, cerebellar cortical heterotopias, gray matter ectopias in both spinal cord and hemispheric white matter, marked ventricular dilatation, and moderate diffuse white matter gliosis. Karyotype was 46XX. A complete necropsy study is presented and all reported cases are reviewed focusing on their phenotypic differences and their nosologic classification. We propose the entity LSS only in cases with symmetric tetrameric polysyndactyly, especially cup-shaped hands and mirror feet, in association with nasal anomalies.