Two known genes (RAI2 and RBBP7) and a novel gene (TL1) were screened for mutations within an affected male from the CXN family and an NHS family by direct sequencing of coding exons and intron- exon splice sites.
Direct sequencing of the RAI2 gene and predicted promoter region has revealed no mutations in the families screened; RAI2 is therefore unlikely to be associated with NHS.