Tsc1^W243X/Tsc1^W243X mutant clones on the adult thorax exhibit a significant increase in the frequency of double bristles, missing bristles, patches of bald cuticle, and delay or premature arrest of the cell cycle, as compared to controls. Bristle twinning in these clones is accompanied by loss of neuronal cells and duplication of socket cells in the external sensory organ.

Homozygous clones in the wing show an enlarged cell phenotype. Homozygous clones in the wing disc are typically larger than the wild-type twin spot. Mutant cells from the posterior portion of third instar eye discs are larger than wild-type cells as measured by flow cytometry, but clearly fall into 2C and 4C populations, and therefore appear to have a normal DNA content. There is an increased proportion of cells in S phase with no evidence of either a G2 block or polyploidy. Mutant cells in the third instar wing disc show a significant increase in size compared to wild type as measured by flow cytometry, have a normal DNA content and are not polyploid. The mutant cells are overrepresented in the S and G2 fractions and underrepresented in the G1 fractions compared to wild-type cells. There is a small reduction in division time compared to control cells.