Arrondel et al. 2002 report finding this variant in an Epstein syndrome case (dominant inheritance), but another variant (S96L) was also present. S96L was a de novo mutation thought to be pathogenic by the authors. R1400W was inherited from the father, who was unaffected, and so was unlikely to be disease-causing. Because the variant was not present in 140 control chromosomes, the authors did not rule out a potential pathogenic impact or modifying effect.
This variant is also present in a HapMap individual, NA12878. Based on this and the presence of the variant in an unaffected father, this variant appears to be a rare polymorphism with no severe pathogenic effect.