Recessive gain-of-function. Codon 393 changed from alanine (GCT) to threonine (ACT). Deg and Tab at all temperatures. Lethal at 15C (embryos arrest at the two-fold stage, larvae survive).

Touch insensitive-at the tail. Degeneration of a small set of neurons. TAB Touch ABnormal).

Animals move sluggishly but are able to back, despite n491. lb125 also partially suppresses the tail touch insensitive phenotype of u38 in cold-sensitive fashion: at 25C -> 0%; at 20C -> 5%; at 15C -> 30%.