Mutation in the FN3 domain which results in a frameshift.
4 base deletion causes a +2 frameshift.
Homozygotes have extremely reduced viability.
Heterozygous males and females show significantly reduced total waking activity levels compared to controls. Heterozygous males have reduced total sleep per 24 hour period and slightly longer daytime sleep latency compared to controls, while nighttime sleep latency is not significantly affected. Heterozygous females have increased total sleep per 24 hour period and show an increase in both daytime sleep latency and nighttime sleep latency compared to controls.