Nmnat¹ mutant clones in sensory neurons in the adult wing undergo rapid degeneration affecting cell bodies as well as axons.

28 day old Nmnat¹ mutant flies containing neuroblast clones exhibit β-axon loss in the mushroom body. γ and α'β neurons are not visible and there is some loss of αβ neurons.

Flies with eyes that are mostly homozygous for Nmnat¹ (due to somatic clones induced using Scer\FRT and Scer\FLP1^ey.PN) with heterozygous patches are smooth with a normal external morphology. Electroretinogram (ERG) recordings from such eyes belonging to young mutants show reduced depolarization and on/off responses. Transmission electron microscopy of lamina synapses from 1-day-old flies with these clones reveal morphological defects; the laminae are disorganized, with various numbers of photoreceptor terminals per cartridge. The terminals contain a fragmented cytoskeleton and misshapen membrane organelles. In presynaptic terminals, the T-bars are amorphous and less electron dense compared to wild type, but they are surrounded by clusters of normally sized synaptic vesicles. However, the size of the T-bar profile, measured by the width of platforms is significantly reduced compared to wild type.