No nucleotide substitutions are detected in any of the cnc open reading frames or splice junctions.
Homozygous embryos have ectopic mouth hooks and cirri, but the median tooth develops normally. The lateralgraten are slightly shortened.
Homozygotes or transheterozygotes with cncC7 display ectopic mouth hooks and cirri in the mandibular region, indicating a mandibular to maxillary transformation. The median tooth, dorsal bridge and other more anteriorly derived structures appear to be unaffected. Transheterozygotes with cncVL110 have the mandibular to maxillary transformation and nearly normal median tooth and dorsal bridge.
Loss of function phenotype differs from that expected of cnc loss of function mutations but the allele has been provisionally classified as cnc based on meiotic map position and failure to complement cncVL110.