Novel Clinical and Genetic Findings in Laurin-Sandrow Syndrome: A Case Report.

INTRODUCTION

Laurin-Sandrow syndrome is a very rare developmental disorder characterized by polysyndactyly of the hands and feet, as well as nasal anomalies. Often, there is associated ulnar and/or fibular duplication. It is caused by microduplications on chromosome 7q36 that encompass the Sonic hedgehog limb enhancer region, the zone of polarizing activity regulator sequence (ZRS).

CASE PRESENTATION: We describe here an individual with triplication encompassing the ZRS region. In addition to the other characteristic features of this condition, he has an unerupted single central maxillary incisor tooth.

CONCLUSION

Laurin-Sandrow syndrome is caused by interrupted signaling of Sonic hedgehog pathway due to duplications encompassing its enhancer region (ZRS) on chromosome 7q36. ZRS plays a crucial role in limb development by regulating the Sonic hedgehog signaling. Nasal anomalies are well-recognized features of Laurin-Sandrow syndrome. Single median maxillary central incisor has not been described in Laurin-Sandrow syndrome, but it is associated with Sonic hedgehog signaling interruption. The presence of nasal anomalies and dental abnormality in Laurin-Sandrow syndrome may suggest a potential role of ZRS in craniofacial development beyond its known role in limb development.