Male‐to‐male transmission in Laurin–Sandrow syndrome and exclusion of RARB and RARG

We report on a father and a son with nasal and limb defects characteristic of Laurin–Sandrow syndrome (LSS) excluding for the first time X‐linked inheritance in this rare condition. Based on a search for genes expressed late during nose formation and early in limb formation we identified retinoic acid receptor B ( RARB ) and retinoic acid receptor G ( RARG ) as possible candidate genes and sequenced bidirectionally including all exons and intron–exon bounders. We identified a single nucleotide substitution in intron 2 of RARB , which is conserved in human, chimp, dog, mouse, rat, and chicken. However, it was located 83 bp from exon 2, suggesting it is a rare polymorphism which does not account for the phenotype. No other mutations were found. This suggests that another yet unknown gene is responsible for the condition. © 2005 Wiley‐Liss, Inc.