spin^N/spin^Δ29 and spin^N/spin^Δ86 transheterozygotes show small amounts of adult escapers, depending on culture conditions. Adult escapers exhibit progressive locomotor defects, such as difficulty in righting after a fall. These defects worsen during the days after emergence and result in death within 5-12 days. The escapers appear morphologically normal except for a subtle, completely penetrant extra wing vein phenotype.

spin^N clones in the retina result in a large number of abnormal membranous inclusions in the cell bodies of the photoreceptors. One population of inclusions contains multilayered membranes often together with partially degraded organelles which are likely to be secondary lysosomes. A second population consists of organelles with a single limiting membrane surrounding many small regularly shaped internal vesicles, which typically represent late endosomes. In the lamina, spin^N mutant cartridges also accumulate large membranous inclusions mainly in the glial cell bodies but these correspond only to secondary lysosomes and not to late endosomes. The inclusions are present in presynaptic photoreceptor projections and postsynaptic monopolar cells. spin^N clones do not affect laminar architecture, rhabdomere morphology, number of photoreceptor terminals per cartridge, or number of glial invaginations per photoreceptor terminal.

Electroretinogram recordings from 1-day-old flies with mosaic spin^E14.1 eyes are not significantly different to wild type. However, electroretinogram recordings from 40-day-old flies with mosaic eyes reveal reduced depolarization in response to light and smaller on/off transients compared to 40-day-old wild-type flies.

1-day-old flies with mosaic spin^N eyes have vacuoles throughout the retina that are not present in controls. The extent of the vacuolar lesion defects progresses with age as 30-day-old flies show an increase in both the number and size of the lesions.