We therefore investigated olfaction in human subjects from families with congenital aural atresia that were heterozygous for TSHZ1 loss-of-function mutations.
Activating point mutations in the N-ras gene (nine CAA (Gln) to AAA (Lys) transversions and one CAA (Gln) to CGA (Arg) transition at codon 61) were detected at high frequency (56%).
Direct sequencing analysis showed that all mutations were CAA (Gln) to CGA (Arg) transition of codon 61, except for CAA to AAA transversion in one case of follicular carcinoma.
Differential hybridization of the polymerase chain reaction products with CAA (Gln) and TAA (Stop) specific probes detected an edited base only in cDNA from CaCo-2 cells transfected with pHEB-354, in agreement with the protein analysis.